It depends a lot on how long you’re going for, how far into Scotland you plan to go, what kind of things you like to see & do and whether you’re planning to use campsites or wild-camp.
If you’re only going up as far as Glasgow & Edinburgh there’s lots on the west coast up through Ayrshire and then you can head east to Paisley Abbey, the Falkirk Wheel and The Kelpies, and the Forth bridges aren’t to be missed, you can then come back down the east coast and stop off at Lindisfarne if you haven’t already been there – but check the tide times! Instead of the A1, the A68 over the border at Carter Bar is a spectacular drive.
Agreed on Applecross. We did that Outer Hebrides tour in 2009, Applecross and Knoydart had been on my ‘to do’ list for about 20 years and finally getting there, in perfect weather, was unforgettable. So much so that of the five most memorable places we went on that 2009 tour, Applecross (& the Applecross Inn), Knoydart (& the Old Forge Inn), Staffa (& Fingal’s Cave), Ulva (& the Boathouse) and Iona, I vowed never to return to the first four again because the experience cannot possibly be surpassed and would only leave a tarnished memory in less favourable conditions. I wanted to savour the images & memories we already have.
We did go back to Iona though on the Inner Hebrides tour four years later. In 2009 the weather was a bit Scottish but on our return we saw Iona Abbey without scaffolding, the old Nunnery without rain, and photographed the medieval church within the Abbey with a decent camera.
If you do get up to the Applecross area, venture over the Ratagan Pass to Glenelg from Shiel Bridge, you can get a really historic ferry to Skye from there and then come back to the mainland on the bridge, to Eilean Donan castle (the one on all the biscuit tins).
Also don’t miss Glen Coe, there’s some great wild camping by the King’s House hotel and if you drive up the west side of Loch Linnhe from the Corran Ferry you get super views of Ben Nevis across the water.
There are a gazillion other places I could recommend but if you give me a clue from the first paragraph above I can give you a better idea
