We did it! We camped! Although I think it was sort of cheating because we got there around 5 pm on saturday, and there was a light rain falling. We were at campsite #1504, right next to the comfort station. At first I thought that was really good, but then later on at night I could hear the door opening and closing and it was kind of annoying, so next time I might ask for one a few away.
Anyhow, we got there and put the tent up, it went right up with no trouble. I think it's called a Wegman or something like that. We put up the rain fly (is that right?), put the blow up mattress in there, and zipped it up and took off for the Magic Kingdom. We were going to do the campfire but at that point it was raining hard enough that we thought ponchoes at the MK would work better.
We ended up staying at MK until midnight, stumbled back to our campsite (totally forgot what color bus we were supposed to get on but the bus guys were really nice-at least we remembered what loop we were in), and pulled the sleeping bags and pillows out of our car and crawled in and konked out. It had stopped raining around 10 pm so everything was fairly dry.
We ended up turning on the fan inside the tent not because we were hot, but the CRITTERS outside made so much noise! An armadillo

kept walking past and making snuffling noises, and there were other interesting non-human noises going on. We were really not used to it, but we thought it was neat. The fan muffled the sounds o' nature enough that we could sleep.
We got up the next morning, the kids and I had totally kicked my hubby off the air mattress at some point during the night and despite the good sleeping bag he said he got a little cold. There's enough room for one more mattress (twin sized) to squeeze in there so I think we'll do that.
We didn't get to make smores or do the other awesome stuff that FW has, so we want to come back and do it again. I didn't want to crack open the suitcases to get our clothes and toiletries for a shower, so we rolled over to OKW around 10:30, rumpled and vaguely smelly, and thank goodness they had a room ready-we totally weren't expecting it, we usually check in early and then call around 3 when our room's supposed to be ready, so it was very nice.
Next time I am definitely bringing some twinkle lights (saw a lot of those), and a suitcase just for being at FW that I can open and get everything I need without messing up the other suitcases.
There was definitely a sense of familiarity and neighborliness that I haven't experienced at the regular hotels and to a somewhat similar degree at the DVC's, but I loved how everyone was expertly chilling out at FW.
Thanks for all the advice, it was an adventure we'll be repeating. Although I don't think I'm going to trade in my DVC for an RV just yet, we're definitely going to be camping more at FW.
ps My husband pulled into the campsite and said, There IS a grill here! I couldn't remember!

Well, maybe I did and just wanted Trail's End that night instead of hotdogs...