I dont think the peeing is the problem, just go if you have to there is always somewhere, jump a hedge if you need,
I always seem to choose the time to go when a car, runner or walkers come by.
For me it would be a nightmare if there was no loo to be seen and i needed the "other"
I dont understand how anyone could use a porta pottie they are sooooooooo disgusting, would rather dig a hole. At least its just your own "stuff"

so ...
always have in your seatpack.......
tissues, hand wipes, trowel, large brown paper bag to cover your eyes so no one can see you as you squat (ostrich)

happy squatting
Scarlet