Im not to sure whether these places rent out pop-up campers but i can give you a few places i know of.
There is one place on 45 going south. exit almeda genoa and it will be on your right-hand side after you pass David McDavid Honda.
There is a place called PP&L on 59 south and beltway 8.if youre going south on 59 its on the left side of the freeway.
Then there is a place on 45 south exit scarsdale. and its on the feeder in between scarsdale and astoria.I think it is called Lone Star
RV.