D.W.
My guess would be even if you found something to go over the pack n play you wouldn't get a restful night like you do at home. When we used to travel to the in-laws all the time my son's routine was always messed up and he never slept very well.
I used to try very hard to keep his eating and nap/bed schedules as close to what he was used to but it was still tough. I used to bring the same books and such that he was used to and do the same bedtime routine and get things calm for him well before him going to bed and that did help him wind down for the night.