My brothers and I did a version of it last year. I live in SW Scotland so we crossed to Arran then Kintail, Oban and Ft William. Then Ullapool and so on. A fabulous ride. Even though I've lived and stravaiged around Scotland all my life this was an exceptional trip. My wife and I doing it again this year. We went mid July and traffic was light. Nae midges! August will be much busier.
https://www.thetriumphforum.com/threads/1st-annual-scotland-road-trip-13th-18th-may-2018.12511/ https://www.thetriumphforum.com/threads/post-your-scottish-road-trip-photos-here.13992/
We don't have a choice about when we go as we work in industry's that shut down for the annual holidays mate.
There are a number of good value bunk houses around the NC500. Check the link below. I spent three nights at the top one pictured, Sleeperzzz at Rogart Station, Pittentrail, and did the quiet inland roads as well as the coast. It's cozy. From personal experience I can also recommend Jessie Mac's in Dunkeld, and the Sail Loft in Portsoy. I've organised a wee trip for a six of us after GMU2019 and have booked the Pitlochry YH, the Kyle of Tongue Hostel, and Morag's in Fort Augustus all of which get good reports. A pal reckons the hostel in Invershin is very good too. If you're planning to go through Glen Coe at all then the By Th Way in Tyndrum is excellent. https://independenthostels.co.uk/highlands-bunkhouses-hostels-bothies/