We tent camped at FW last July and used only our car for the 16hour drive.
We had a large tent and another screen room to put over the picnic table, air mattress for DH and I, two large coolers, cooking supplies, sleeping bags, four camp chairs, and assorted other camping necessities. It was a tight fit in the car, but we managed to squeeze it all in using a hitch for the back (which held the two coolers). You will want the extra screen room if you are tenting, it rains almost daily and it's nice to have some dry space to cook/eat/relax.
The pad is sand which drained very well after the rain, but you have to be careful going in and out of the tent with shoes on or you'll end up with a real mess inside. We kept a shoe bin by the door of the tent and took our shoes off when entering. We also had a small hand broom and dust pan to keep it tidy.
One thing we brought that we didn't need was a window a/c unit. We thought the tent would be too hot to sleep at night. It was actually quite comfortable and we found the a/c made the tent too cold. Go figure. I would probably still bring fans or a/c because you could get a heat wave, but it wasn't a problem for us on that trip.
The loops at FW are pretty compact so the comfort station was just a short walk. It didn't bother us to make that short trip in the middle of the night, but your comfort level may vary.
The comfort stations were always clean and well stocked. There were 4 stalls and 4 showers I believe (maybe 3?) The showers were set up with an inner shower space, and outer dressing space, separated by a curtain so your clothes/towel stayed dry and you had some privacy to change.
They were just big enough (I've been in some that were claustrophobic tight), but not huge. If you need to help a small child shower they would be pretty snug. There was a larger handicap stall/shower, which would be helpful for that purpose. Only once in 5 days was there someone using the showers at the same time as us (and our loop was 90% full) so I think you could use them as a family shower without inconveniencing anyone who had a medical need for the space.
We had no problem with security at our site, other than a few pesky animals that got into some food we didn't have sealed up well. Doh. We left our electronics in the tent while we were in the parks each day, because I felt like the heat of the car might damage them more.

There is always a risk, but it worked out okay for us.
The campground is very spread out. We didn't have any bikes or a golf cart and we did okay with getting around. But, it might have been nice to have another option if we were staying longer and using the campsite activities more. (We were in the 1500 loop which was walking distance to the pool area, which was a big help. I wouldn't have wanted to take a bus back and forth just to swim.)
Hope this helps. We really enjoyed our stay at FW and hope to go back again some day! It was so relaxing compared to the values we had stayed in before.
Enjoy your trip!