What's the big problem with just holding it in for 12 to 36 hours?
The big problem is that it's about as realistic as suggesting I hold my breath for the same amount of time.
Regardless of altitude (this happens here in the lowlands of Ohio, too, I promise), when you have to go, you have to go, and additional hiking to arrive somewhere to do it, only makes the urge to go all the more acute (been there, done that many times, despite desparately trying to "hold it" for as long as possible -- usually don't even make it to 12 to 36
minutes, let alone 12 to 36 hours!).
CaT