where to buy a replacement mattress

Thanks for all the suggestions

IKEA

I bought mine on ebay. med firm 10 inch memory foam just less than 300. sometimes you can fit a reg queen in them but you can get either.

We bought Spa Sensations memory foam mattresses from Walmart online based on a previous recommendation from this site and the tons of positive reviews. I left the one on our "queen size" at full length which was probably 6" longer than OEM mattress, and on the bunk which has a diagonal cut I used an electric carving knife and made it so easy.

I could never rationalize buying something as important as a mattress without first laying on it. That’s why, when we needed an RV King mattress for our fiver, I went to a mattress factory store, tried out their various lines on the showroom floor, then chose a foam mattress which the made to fit our fiver.
Why not call Golden Mattress Company in Houston and see if they’ll make a mattress to your size, then go down and lay around their showroom?
http://goldenmattress.net/about_us

I bought one of these & love it.
https://www.mattressinsider.com/luxury-rv-mattress-memory-foam.html

We bought an RV queen sized memory foam mattress years ago for our motorhome from bedinabox.com and got a good deal at the time. More recently though they have been pricey.

Our most recent purchase for our travel trailer was a full queen from walmart.com.

We kept the motorhome for a couple of years after replacing the mattress and had no complaints. We've had the travel trailer for about 10 months and have had no complaints with the mattress we put in it either.

We replaced the "RV queen" in the travel trailer with a standard queen. I pulled the plywood section out and used it as a template to cut a longer plywood piece. The only issue, and this would have been an issue even if we hadn't changed sizes, is that the memory foam is much heavier than the thing they tried to call a mattress the manufacturer shipped the trailer with. This means the gas struts aren't strong enough to hold up the plywood to access the under bed storage. We could replace the struts with stronger ones and may at some point but for now I cut a length of 1x2 to support it.

At least check out www.verlo.com.

Regular mattress stores have RV queen size.

Bought a memory foam from local store cut it off with a bread knife,put a mattress cover on it.