In reply to rodw:
As above, The Hen Hole in Cheviot is a great spot, camp just above the last waterfall, or an alternate is Bizzle Crags, nice large grass spot there if not as remote, both places accessible by leaving car at Hethpool. I wouldn't leave a note in the car though, bit like saying to thieves "you have 2 days to rob me before anyone will notice" you can contact police or if you have someone at the same address as vehicle reg, just leave plan with them. Also good parking at NT park at Alwinton or Barrowburn for access to Davidsons Linn etc. Pennine Way runs length of border ridge with good path, any other summit away from this will be a bog walk! Also parking up Ingram Valley just past Ingram, though its popular and not as secure, bad time of the year as far as thieves go! having said that I don't want to put you off, its not Wales! Enjoy looks like good weather next week