If you have time I’d not drive up the A9 to Inverness and take a detour to the road that takes you alongside Loch Ness. IE - cut off the A9 at Dalwhinnie along the A86 then up the A82. It’s fairly stunning.
Also, if you have the chance and time head right to the north of Scotland and drive along the A836 and A838 from Thurso to Tongue and Durness and then down the west coast A835 to Ullapool and onwards to Skye. It is an absolutely beautiful drive, but some of the roads are tight so it takes longer than it looks because of all the stop offs for pictures and to take in the scenery. I’d knock off one of the nights in Inverness to do this.
Glencoe…fucking WOW!!!