Perth and Kinross is the transitional county — Highland in the north, Lowland in the south, with the River Tay running through most of it. It's agricultural country for the most part, prosperous and well-maintained, with a series of decent market towns and increasingly dramatic scenery as you travel north.
Perth itself is a compact, comfortable city on the Tay. It was Scotland's capital for a period and Scone, just north of the city, is where Scottish kings were traditionally crowned — the Stone of Destiny was kept here until Edward I took it to London in 1296. Scone Palace, still lived in by the Earl of Mansfield, is open to visitors and has a good collection of art and furniture. Perth's town centre is walkable and has some good independent shops; the art gallery has a strong collection including a large number of works by the Perthshire-born artist J.D. Fergusson.
North of Perth, Dunkeld is one of the more pleasant small towns in Scotland — cathedral ruins on the Tay, good walking in Hermitage Woods nearby, and a small collection of restored 17th century houses that make up the cathedral quarter. Pitlochry, further north, is a Victorian tourist town that has been doing what it does since the railway arrived in the 1860s. The fish ladder at the hydroelectric dam, where you can watch salmon making their way upstream through a viewing window, turns out to be more interesting than it sounds. The theatre there has a good summer programme.
Aberfeldy, in the Tay valley to the west, is a small town with Wade's Bridge of 1733 crossing the river, Dewar's distillery and a good bookshop. Kenmore at the eastern end of Loch Tay is a well-preserved planned village. The crannog reconstruction on the loch gives an impression of Iron Age lake dwelling life that's hands-on and accessible. Crieff is a market town with the Glenturret distillery (which claims to be Scotland's oldest) nearby. Blairgowrie in Strathmore is the centre of Scotland's soft fruit country and has a busy, unaffected character.
The northern part of the county includes the passes of Glen Shee and Killiecrankie — the latter the site of a significant Jacobite victory in 1689. Kinloch Rannoch at the western end of Loch Rannoch is a small village at the end of a long road with good access to the high country beyond.