Get something bendy, getting mattresses in an out are a pain and so is changing the sheets!!! I use one of those areo beds and it is awesome!! easy to maneuver easy to store and easy to change the sheets!
i have a used hospital foam bed which is the best i've found for horse camping.
it's a couple of different types of foam, twin size so easy to handle.
but, i do not sleep in the gooseneck, i sweep out the horse space, hang my mosquito netting from the ceiling and set my bed up on a few bales.
another bale covered with a saddle pad makes a table and the whole set up is at a comfortable height thanks to being on top of the bales or shavings.
it's the best, no bugs, lots of room to move around and plenty of ventilation.
it looks so luxurious that i've been accused of running a bordello out of my rig,lol, but i'm just getting comfy!
We bought a mattress specifically made for RVs, however, you will want a foam topper because there is no box spring so the mattress alone was uncomfortably firm. When we tried it in the store, it of course had a box spring and we (duh) didn't put that into consideration when we bought. Queen size fits quite well but you may want to go with a full so you have room to either side for storage.
Yogurt - If you're so cultured, how come I never see you at the opera? Steven Colbert
I have a featherlight trailer. I use a foam base that I picked up at Joanne's (get a coupon before you go as they are a bite spendy) and topped with some memory foam. Very, very comfy. I used to have a regular mattress but springs were starting to pop out and a regular mattress is hard to get in and out. The new mattress is a bit shorter in height so I also gained some head room.
I have a 7'6" wide 7'6' tall Sundowner and have a queen mattress. The length fits perfectly plus there is plenty of room on each side for the remote, drinks, etc.
We bought a regular innerspring mattress, but measured how tall it could be so we could still sit up in bed, put on sheets, etc. I think we got a
7"-8" mattress. It was about $400 on sale. It is surprisingly comfy for a cheap mattress.
For our previous trailer, we bought a really cheap ($200) really thin queen mattress - 5" or so - and then bought a 4" memory foam topper. That was a VERY comfortable set up.
The mattress is easy to get into the gooseneck if you have a walk through door.
We tried an air mattress and it was horrid. Also the 4" foam mattress that came with our Sundowner was not comfortable at all. Plus it was a full rather than a queen.
I really didn't want to spend that much for a mattress for the trailer, but after a day of riding and camping it is heaven to get into a nice bed. And this time if we sell the trailer we are keeping the mattress!
I have a Hart with a smal LQ and it came with a full size inner spring matress in the neck. We camped two weekends ago and it's great when it is just me but when my husband showed up it was tight! Our trailer is only 6' 8" wide and the nose tapers, but the full sized matress doesn't even extend wall to wall. We are now looking at purchasing a memory foam matress that we can cut to fit the entire gooseneck for more space.
One thing you may want to watch is the thickness of the matress. Some goosenecks come "dropped", meaning they have been lowered, allowing for more headroom. If yours has not been dropped, you may want to consider a thinner matress for more headroom.
I've seen comments on Horse Trailer World and have been doing research on the memory foam. Wal Mart has them starting at about $150 and you can find them at any matress or furniture store for more than that.
We use a queen sized Coleman air mattress topped with a thick egg crate topper. You don't want an air mattress without a topper of some sort- the mattress will be cold otherwise. Sleeping alone on it is easier than sleeping on it with DH. If he moves, I move LOL. But what is nice is how easy it is to change the sheets- I can wrestle with it pretty easily.
I worry about a real mattress given our heat and humidity. I would not want to sleep on a musty mattress. The air mattress can't get stinky LOL.
I may try a futon mattress with an egg crate topper, and use a bed-bug type of zippered cover...that might keep it fresh and resist the moldy musty smell.