I've been writing down all your suggestions and researching how long they'll take. I'm beginning to suspect my original estimate of 10 - 12 days is very optimistic, most walkers seem to take 16 -20 days to walk just the Pennine Way - unless i just walk up the A1, which would be mind-numbingly boring.
The Northern part looks fairly straight forwards, it's more the Southern Part where there seems to be endless winding paths rather than anything fairly direct between towns.
Another option occurred to me that i'd like to run past you guys, what if i follow the East Coast Main Line most of the way up? Does anyone know if there are trails running alongside significant sections of that route? and probably increase my estimated walk time to a still probably over ambitious 20 days, aiming for 30 mile days. (i'll get some good training in before starting)
https://commons.wikimedia.org/wiki/File:East_Coast_Main_Line_Map.png [nofollow]Thanks again.