Bin the A9 at Dunkeld.
Head east to Blairgowrie then north on the A93 Spittal of Glenshee, Braemar and onto Tomintoul. One of the best rides in the country.
Grantown upon Spey/ Boat of Garten are good places to stay. As is Aviemore which would allow a ride up into the west side of the Cairngorms for more spectacular views (an hour or so.) Also a great bit of road.
Head west from Inverness to Ullapool (great place) and up hugging the coast round to Tongue and back south via A836 Altnaharra road. Would not bother with the east side. West is best.
Head south via Loch Ness A82, Spean Bridge (Commando Memorial,) Glencoe, Crianlarich then either stau on the A82 and down the side of Loch Lomond or via A85/A84 Callander (which allows doing the A821 Dukes Pass)
Back at Stirling / Glasgow / Central Belt for the easy m/way back down the road.
Not even mentioned Isle Of Skye/Plockton/Applecross/Torridon or Isle of Mull but basically my advice is dont have the NC500 route as cast in stone and smashing yourself to get up there and back to "do it." You'll miss a lot of the top stuff. Find you own way...ish!

Maps oot! Happy planning!
