I guess your pop up doesn't have a ceiling exhaust fan??
Many of us have maxxair or fantastic or creatabreeze 12v fans in
our roof. Mine is right over the bed and we can have a nice downward
breeze any time. We use it all the time when camping off the grid.
I also have a little table clamp oscillating 2 speed fan that runs off
a cigarette socket 12v. I bought it years ago for tent camping at the
lake. You can still get them and I would not dry camp in summer
without one or the other!
Visit Amazon.com and search 12 volt fan in automotive.
You can see several examples. Walmart probably has them as well
but they're down for site maint and I can't check right at the moment.
Good luck and Happy Camping!