Argyll and Bute

• is the eastern boundary of this region. The National Park includes the west bank of the loch, Loch Goil and Loch Long in Cowal, and the "Arrochar Alps" or Forest of Argyll. Argyll is the wrong side of Loch Lomond for the "The Trossachs", Loch Katrine and Queen Elizabeth National Park. By road up the west bank, is the first village, very tourist-trappy, and bypassed by the busy A82.
• At (note the spelling) there's a junction. Stay on A82 by the loch to reach Ardlui, Crianlarich and Tyndrum, for routes to Oban, Glencoe, Fort William and Skye. Or turn west on A83 past Arrochar and the head of Long Long to climb towards "Rest and Be Thankful", the side road for Cowal, then along Loch Fyne for Inveraray, Tarbert and Campbeltown.
• is a small seaside town with several notable buildings, some by Charles Rennie Mackintosh.
• is a small village west of Gare Loch, with a ferry from Greenock.
• Cowal is the peninsula west of Loch Long. So close to Glasgow, yet so remote and unpopulated, because of the long sea lochs that separate it from other areas. Once visitors have struggled over "Rest and Be Thankful", they're keen to get past Long Fyne and motor on west; they may not even notice the road turn-off that doubles back into Cowal.
• is the usual way into Cowal, by ferry from Gourock. It has botanic gardens and a summer Highland Gathering.
• is usually reached by ferry from Wemyss Bay. It has a Victorian fernery and the flamboyant Mount Stuart House.
• The main road to Kintyre (A83) runs down the west bank of Loch Fyne.
• is a remarkable 18th C planned town: it and the castle were entirely rebuilt by the Adams architects.
• is at the western end of the Crinan Canal, which enables small vessels to reach the Atlantic coast and Hebrides without sailing round the Mull of Kintyre. It's a good base for exploring Kilmartin, which has a remarkable collection of prehistoric, early Christian and medieval remains.
• is a small fishing village, linked by ferry to Portavadie on Cowal. Five miles west is Kennacraig, with ferries to the Hebridean islands of Islay (from which you reach Jura) and Colonsay. To the south, a ferry runs from Claonaig to Lochranza on the Isle of Arran.
• is an island 3 miles west of the mainland, a 15-minute ferry ride from Tayinloan. It has botanic gardens and standing stones.
• is at the end of this long, long road that brings you onto the scenic Mull of Kintyre. In summer a small ferry plies to Ballycastle in County Antrim, Northern Ireland.
• Along the Atlantic Coast: the usual approach is by A82 north past Loch Lomond and Crianlarich to Tyndrum, then west on A85.
• has two "iron age" sights: the well-preserved remains of the 18th / 19th C iron furnace, and the remarkable modern engineering of Cruachan deep in the mountainside.
• is a transport hub, overlooked by the Victorian folly of "McCaig's Tower". There are ferries to the Hebridean islands of Mull (for Iona), Coll, Tiree, Colonsay, Barra and Lismore, also to Kerrara which is close inshore and effectively part of Oban.
• is connected to the mainland by a bridge. Ferries make the short crossings to the island of Easdale and Luing. Boat trips sometimes venture beyond to Scarba and into the straits, site of the seething whirlpool of Corryvreckan. At the right state of tide, its roar can be heard ten miles away. Just beyond is the north tip of Jura.

Argyll and Bute have only been amalgamated into one region in relatively recent histor, only being created in 1974. All through the Middle Ages and into the post-Union period, the Duke of Argyll ruled all of Argyll. The Isle of Bute was held by other families, and formed part of the county of Buteshire along with other islands in the Firth of Clyde.
The Duchy of Argyll, although not having the same boundaries as the modern council area, was a major political force in Medieval Scotland. One of the most famous, and amongst certain clans, infamous clans of western Scotland, the Campbells had their seat in Argyll.
Many works of fiction including Robert Louis Stevenson's Kidnapped have featured the wild and rugged coastline of Argyll as a setting.
Though less well known than Argyll and lying some way to the south, Bute has its own place in the regions past, primarily as the target of raids and clan rivalries.

Argyll and Bute is one of the major centres of Gaelic and Gaelic culture. this said, the sole universal language is English. In towns like Oban you may find Gaelic speakers as well as recent immigrants form eastern Europe. In effect though, everyone speaks English and communication should not be a problem. One points of caution though, the road signs are all in Gaelic and English and often have Gaelic first. If you can, make sure to read the full sign to find the English place name.

By plane

(GLA) is the principal airport for this region, with a good range of European and UK flights. For long-haul use Manchester (MAN) or London Heathrow (LHR) or Gatwick (LGW).
By rental car from Glasgow Airport, head west on M8 to Greenock or Gourock for ferries to Cowal, or cross the Erskine Bridge for A82 north past Loch Lomond.
Campbeltown is on the mainland and barely 80 miles from Glasgow, so considering flying . . . seriously? Yes, but it's 180 miles along a twisty road, clogged with traffic in summer. There's a flight twice a day from Glasgow to (CAL), five miles west of Campbeltown. This is a good alternative route for Gigha and the Kintyre peninsula as far up as Tarbert / Kennacraig.

By train

Your first task is to reach Glasgow, which has rail connections throughout England, Scotland, and (via Cairnryan) Ireland. From Wales change at Crewe.
Six trains per day run to Oban along the West Highland Railway from Glasgow Queen Street, taking 3 hours. The route is north via Dumbarton, Helensburgh, Rhu, Garelochhead, Arrochar / Tarbet and Crianlarich where the train divides: half continues north to Fort William, while half goes west via Taynuilt to Oban. An overnight sleeper also runs from London Euston via Glasgow Queen Street and Crianlarich to Fort William but doesn't connect with the Oban trains.
For the Isle of Bute, take the train from Glasgow Central to Wemyss Bay then the ferry to Rothesay.
Trains also run from Glasgow Central to Gourock, which has ferries to Kilcreggan, and to Dunoon on the Cowal peninsula.

By road

The usual approach is by A82 along the west bank of Loch Lomond to Tarbet. (From the south or east, bypass Glasgow on M8 / M74 and cross Erskine Bridge.) Stay on A82 northbound for Crianlarich and Tyndrum, then A85 for Taynuilt and Oban. Or turn west onto A83 for Arrochar, Loch Long (where the side road to Dunoon and Cowal branches off), Inveraray, Lochgilphead, then south to Tarbert, Kennacraig, and all the way down to Campbeltown. Buses from Glasgow Buchanan Street ply these main routes.

By ferry

Ferries sail roughly hourly between Wemyss Bay and Rothesay on Bute, between Gourock and Kilcreggan, between Hunter's Quay near Gourock and Dunoon on Cowal, and between Portavadie on Cowal and Tarbert (Loch Fyne). A small, infrequent ferry runs between Claonaig near Skipness on Argyll to Lochranza on Arran. For details of the Hebrides ferries, see Islay, Colonsay, Mull, Coll, Tiree and Oban.
The Five Ferries is a cycle route of 51 miles, starting in Ardrossan in Ayrshire, crossing Arran to Kintyre then Bute and back to the mainland at Wemyss Bay. There are steep gradients along the route and it's often done as a charity challenge. From the first ferry landing at Brodick on Arran you'll have 75 min to cover 14 miles to catch the second ferry from Lochranza to Claonaig, otherwise your day unravels.

You probably need a car. Between points along the major routes there will be a couple of long-distance buses each day, and six trains for stations to Crianlarich. There are local buses around the main villages but most are timed for the daily school / shopping run and are not much help with sightseeing. However, Bute and Gigha are small enough to explore by bike.
May-Sept a ferry potters up Loch Lomond from Balloch (frequent trains from Glasgow Queen Street). On the west bank it calls at Luss, Tarbet and Inveruglas; on the east at Balmaha, Inchcailloch island, Rowardennan and Inversnaid.

• Castles: Inveraray is elegant, the rest are picturesque ruins. Choose from Carnasserie near Kilmartin, Carrick, Dun Ara, Dunans on Cowal, Dunstaffnage near Oban, Duntrune, Kilchurn, Kilchrist, Kilmartin, Lachlan, Poltalloch, Rothesay, Skipness, Stalker . . .

• Visit a distillery: Oban has one whisky distillery, Campbeltown has three plus a gin distillery. They all offer tours, as does the brewery near Inveraray.

• Beer is brewed by Fyne Ales near Inveraray.
• Oban has a malt whisky distillery.

Argyll in general is very safe. As with all rural parts of Britain crime is remarkably low. There are occasional incidents of theft in the major towns but these are very rare. It is not uncommon for people to leave their doors unlocked almost all the time. Although all normal precautions for travelers are advised there is little for tourists to worry about in terms of crime in Argyll and Bute.
Environmental hazards
In winter many roads in Argyll can, or at the least in the last two years have, been covered by snow. If you are not accustomed to driving on snow then extreme caution is advised during the snow. Even when there is no snow there can often be ice in winter and although less obviously dangerous Ice is a more common danger.

See this map for places with Wikivoyage articles nearby.