A little non specific but I can guarantee that round the top and down the west coast you will be stopping at every layby if the weather is decent. Actually I've been up the east coast Inverness round as far as Melvich and that's not too shabby either. If you're doing it slow time, if you don't mind a walk some of the inland lochs down the west coast are beautiful (some of them are fairly long walks.....). If you're interested in wildlife at all I can reccomend a trip out with Gairloch Marine Wildlife Cruises. Ian's a marine biologist and really knows his stuff, and doesn't intrude. Look out for white tailed eagles, seals and otters. They're right down that coast. Get among the mountains and you may be lucky enough to see golden eagles. It can get a bit frustrating sometimes seeing a stunning photo op and not being able to stop (please drive single track roads as they're meant to be driven and never be tempted to use a passing place as a layby). I've had my partner drop me off then had to walk a long way to find where he's been able to stop and wait....
A few places I know quite well:
Anywhere around Ullapool
Little Loch Broom
A lovely short walk from Mellon Udrigle (nice beach there too) round Rubha Beag. Look for seals
A shortish walk from Poolewe round Loch Kernsary. Look for red deer
Red Point
Loch Maree
Loch Clair/Loch Coulin. Great views of Beinn Eighe and Liathach
Loch Torridon
Shieldag
The mountain road to Applecross is spectacular if you get the weather, if you're not stuck in a convoy spending more time trying not to scrape either your vehicle or someone else's than looking out and depending on the size of your camper van. Please just ignore the folk who say 'I took my massive motorhome over there and it was fine'. They cause chaos. When you see some poor supermarket delivery driver having to reverse his van up a steep hill round a tight bend with a sheer drop just over the not-very-high barrier it makes you think. I've done it in May, on a day of high wind and low cloud (could barely stand at the top and the view - there wasn't one) and it was mobbed. The coast road in is lovely.
Places to stay I can't reccomend anywhere other than Sands and I really can reccomend it. Stayed there more times than I can remember. The sunsets on that coast are stunning.
As Dave says you may be midge free but it's unlikely they won't find you somewhere. Or it could be hoaching in them. Pack the Smidge.
The NC500 has a bit of bad press from locals and it's easy to see why. Be sensible and considerate and you'll love it.
Good chippie in Gairloch...........