Long Rides and Nature Breaks

[TsPoet]

I know this has been covered, but I couldn't figure out what to search on!
I'm seriously thinking of riding the Sebring 12/24 hr race
http://www.bikesebring.org/
On some other forums, the guys are talking about routes for this race and where you can/cannot stop by the side of the road, and if you can/cannot in some places after dark.
There is one pitstop at the turnaround point for the 100 mile loop, but it's "busy" and another for the shorter loop, but the experienced guy's seem to be suggesting that should be avoided, too.
As a long time backpacker, I've got no problem with finding a bush out in the wild, but what about on the side of a road by and orchard, in the middle of a crowded race
I think I may order a freshette!
What do you randoneurs and/or ultra racers do?
(Watching Graham Norton last night, some female English marathon runner apparently stopped in the middle of a race to go "#2" and a photo of her doing that was posted all over the place!)