200 in 24 should be failry straight foreward, Monksie’s doing 190 ish in daylight in a couple of weeks. I attempted to do the same but couldn’t find time to do any long rides so wont be.
I found that after about 5 or 6 hours it just becomes a case of energy in = energy out so as long as I kept eating the legs would keep turning, speed dropped a little, but not as much as I’d have expected it to (dropped from 15mph average to about 13).
Mentaly it’s a f**** joke though, after 7 hours I started talking/swearing/crying to myself, and not in a concious kinda way like you do on an MTB trying to psyke youself up for a jump, the first i was aware was wondering what the voice was in the middle of nowhere!
On the plus side there’s not much that beats the feeling of setting off just after after dawn, and getting back and looking out the window and the suns gone down. Propper all day rides!