Yeah, I do 2-3 hour enduros. Pace yourself, dont burn your energy from the start. Kind of like running a 800 or 1600M in gym class, wait till the last lap and let loose, depending on how long the laps are. You don't see many people stopping b/c they pace themselves. Ride about 70%, take it a little slower in the more technical areas, and remember you're having fun, then when you see you have a lap or two left, maybe even 4 or 5, LOL depending on how long they are, give it hell. If you ride a consistent pace, and see what lines to take and which ones arent so brutal, that will help out as well.
You probably wouldn't look like a jerk, but maybe a CHUMP LMAO. j/k. Buy a camelback if you don't already have one, and maybe a twist throttle or a thumb assist as it will get tiring on the thump.