Anybody who's been, or who interacts with tourists in Scotland, please chime in.

I'm going to fly in to Edindurgh next summer and from there will need to get around with some degree of independence. I want to visit Edinburgh - the Cairgorms - then Inverness with day trip to Culloden and Speyside - then cross over the country to Inverary - then down to Dumfries - Redesdale (Borders) and possibly a day or two in Glasgow on the way south from Argyll.

How do you all achieve this? Buses? Rail? Rent-a-car?