I'd be up for that. You've got an advantage, what with being rather close to one end already.
Charlie The Bikemonger, a hero of mine and occasional contributor to this forum, rode an SS mtb from Swanage to Scotland for the Champs last year. I think I'd choose a road bike for a long journey on the road.
I actually find any distance easier on SS, short or long, on-road or off-road. I commented to someone the other day that gears and suspenion are simply devices to compensate for rider deficiencies, and the actual, physical amount of work done is less on SS for a given distance - which is all true.
It's necessary to be strong and supple to ride singlespeed with confidence. Singlespeed has made me strong and supple. I'm a confident singlespeeder!
STEAL WON!