Flying FR is made out to be like hell on earth, but it's not really that bad. You're fortunate to be flying them in the summer, as it decreases the likelihood that weather will make a mess of things for you.

The seat pitch is not all that different from any other carrier's economy class, once you factor in that there are no seat back pockets jammed with magazines. The seats don't recline, but the flights are short, so it won't really matter. If you and your party meat the exit row criteria, try to snag one upon boarding. (I got an exit without paying for priority boarding just by ensuring to queue up early.)

They are sticklers for rules (size and weight) when it comes to carry-on baggage, so read the rules, read them again, and read them a third time. Then follow them carefully to avoid being hit with a charge at the gate. Make sure you do online check-in and have your boarding pass. (Print a few copies and stash them in different locations if you're prone to misplacing things.)

The in-flight experience isn't awful. They will spend the entire flight trying to sell you things, so bring headphones and zone out.