Toileting and the overnight stay

Up north michigan wrote:
We will be taking our first long trip in our motor home soon. For a single overnight stay before we reach our destination, we are staying in a Wal-Mart parking lot. I have heard from others that you don't want to use your toilet while travelling. Am told if I need to use the facilities during the night, I should go into the store and use theirs. By the time I do that at 2am I will be fully awake! Besides, when I gotta go, I gotta go now. I probably wouldn't even make it. So, do I get a 'ladies' urinal funnel and go in a jar to be emptied later? Get a box of heavy duty depends? Or do I just use the darn indoor toilet? Hey, I'm older now and my bladder isn't what it used to be! What do some of you other ladies do? HELP!