Outstanding roads, beautiful scenery, fantastic way to spend your time, I can't recommend enough. Best to plan petrol stops, they can be a way between, and it can be a little more expensive than further south. If you're staying in B&B/Hotels, they can get booked up at that time of year, and, again can be pricy sometimes; there are not so many campsites if you're looking to go that way (although that may have changed by now as it is getting more popular)- wild camping is a possible, I guess but I didn't actually try it. Plenty of industrial strength deet for the midges- if you have never been up that way before, they are fierce. The deet doesn't stop them, but it does let them know they're being naughty! Have a great time and a safe ride.
Done it East to west , but never headed back to inverness ,we went down to the Torridon mountain pass https://www.google.com/maps/place/Torridon,+Achnasheen/@57.5333115,-6.0346014,9.01z/data=!4m13!1m7!3m6!1s0x488e618b4e88b1f1:0x61bb8e8840f4772e!2sTorridon,+Achnasheen!3b1!8m2!3d57.5468767!4d-5.5133569!3m4!1s0x488e618b4e88b1f1:0x61bb8e8840f4772e!8m2!3d57.5468767!4d-5.5133569 then on to Applecross highland games over the Bealachnaba pass.N.C. 500+
Done the west half. Awesome. Accommodation was a bit scarce. An a bit pricy. We got luck with midges. summer months soon as you stop in the open they want to be biker mates. So environmentally friendly (not deet) is advisable.
We're going to be carting the wife's wardrobe around some of the NC500 in about 3 weeks on a VFR - apparently, if you're up for some instant scenery, it's best to head for Inverness and cut straight north-west, through the mountains.