Good luck!
A mate of mine did it last year (northern route, clockwise). He said it was an incredible experience but very tiring - had to pull over somewhere north of the border for a snooze on a park bench. I'd like to do it myself and I was intending to do it last year but couldn't raise enough funds to get the bike up to standard to take on 1000 miles.
Again, best of luck, and get some bum cushioning.