we have AC in our pop up (put it in specifically for a August FW trip about 5 years ago - camped in FW in Oct without it and didn't need it. Needed it in August though!!!!).
i have also camped in tents with friends (not at FW, but in the south in July, Aug) and holy smokes yes, we needed AC. nights were very hot and humid without it.
much like carol described, they put the small AC unit (
walmart cheapo) on a milk crate right outside the tent "door". the crate is entirely outside - the AC unit is sticking in the door by about 4-6 inches. they found that digging or scraping a very shallow trench where the drips were landing helped them run away from the tent door, so as not to have a muddy mess outside the tent. they then zip up one zipper and zip the other zipper down to seal off around that unit as much as possible. my friend had rigged some foam around there was well to fill in the small gaps left. Wow did that cool that thing off.
i recomend that you vent at the other end of the tent, or (if using a multi room tent) in the rooms where you will be sleeping. condensation can build up and make things dampish.
they also wrapped the connection where the power cord went into the extention cord (used and outside grade extention cord) with several layers of electrical tape to keep out rain.
they (and we with our pop up) generally don't run it all day, just pop it on when we get back and within 10-15 min it is nice and cool in there. We messed up and left it on all day at FW once and came back to the artic tundra in that camper.