I don't get saddle sore generally for the first couple of hours, and then it starts creeping in. DD took Bill and I, 8.5 hours last year. So my @rse only hurt for the last 6.5 hours really. The last couple of hours were ungodly. I don't know how you prepare yourself for that sort of time in the saddle, short of doing the Tour de France. I did liberally apply Bum Butter, not sure if it helped, or if the slimy feeling in my pants was just a pain distraction. From what Bill said last year, I am half expecting him to turn up with a motorbike seat with a pillow gaffer taped to the top!
The problem is as you get more tired you spend more time rooted to the saddle. With discipline ( and a little will power) one can take every slight incline or small rise to drop down the block and rise from the seat.. maybe time it with a jelly baby or sip from your bidon? Don't wait till it's aching before starting or chances are.... it's already too late.
Then the mind games begin..... tick tock - miles, bum...
and London to Brighton and back in 10 hours or so. Neither remotely fast but a lot of time in the saddle. Sore bum but much less so than neck and shoulders.
Cheers. I'm sure TB will be with me so you might want to get one for him too 
). But, hey ho, thankfully I don't need those skills to put a meal on the table else I'd have died of hunger by now 
