Two friends and I camped out at Fresno in the fall in my 2H BP and had a blast! We cleaned out the back of the trailer, put down a tarp and a blanket, then the air mattress. It definitely got cold…since we weren’t able to completely shut the doors it was also a little damp. But, we lived. The first couple of nights (third night it was just myself and one friend) I slept on a camping mat in a sleeping bag in the dressing room, which is huge. My friend brought her camp stove and we have a couple big coolers with food, drinks, and a large water jug. We showered one night (particularly cold and dirty) by going to a local gym and paying to use their locker room. They didn’t charge us, but it would have been like, $7/person, and they had hair dryers, soap, etc. 
I camped out in the same rig at Galway in the spring (still chilly) but was smarter this time. I put the air mattress in the dressing room and all the tack in the back. I have a portable charger unit that was a Christmas gift one year. Best investment you can make. I used it to blow up my mattress and power the clamp light.
Sleeping in the dressing room made a huge difference since it has carpet and was completely sealed. During the day I had just the screen door closed so it got plenty of air. Also had a large cooler of drinks and snacks. A camp stove is a great investment and is on my list of things to get if my horse stays sound. I’m also eyeballing the truck bed tents, but the air mattress in the dressing room is super easy and pretty comfy since it’s a tall one. DH and I managed to fit on it!
