Sage advice from you all - thanks.
My trip has been put back a couple of weeks now, so bearing in mind UA's comments, I'll probably fly in to Dyce initially (after checking when the busy times are), and then go and check out Insch when I'm a bit fresher - I agree it's probably a good idea not to looking for a hard-to-find, tricky-to-land airfield after a 3 hour flight - not for a 60hr PPL anyway!
Again, thanks for all the help.