I am going myself on 18th June for 8 days.
Ive done Scotland many times and have to say its a fantastic place to visit, specially on the bike.
My advice would be to plan several places you would like to see each day to break the journey up.
Seriously its not something to be rushed.
I see people doing the NC500 in 3-4 days and that included getting up there and back! WTF
All that happens when you do that is you need another visit to do it properly lol
Im setting off from Rochdale and going the non motorway route.
Heading through the Forest of Bowland,
through the passes at the lake district,
through Galloway forest park and enjoying the raiders forest drive if its open.
through Ayr to Glasgow
then Loch Lomond and The Trossachs National Park up to Fort William and Ben Nevis,
straight up past Loch Ness to Inverness and the official start of the NC500 I will work my way east to west back to Inverness.
Then set off back through the Cairngorms down to Falkirk to see the Falkirk Wheel
Down to Northumberland National Park and Kielder Forest
Through the Yorkshire Dales home
there is more to it than that, as there are many stops and things i want to see, but you get the idea.
I will be mixing Campsites and wild camping
I planned this for last year and we all know how that turned out... i refuse to replan it this time lol
oh also check out this guys videos, a series of about 6 i think
Worth watching them all back to back when the mrs goes to bed lol
He does something he called the NC767 but it gives you a good idea of what to expect.