Mattress Size & Thickness Recommendations (Bigfoot 2500)

They are queen size or 60 x 72 in both on my campers, but I would advise to measure it as who knows what manufacturer did on the camper.
I had 1 memory foam topper simply deteriorate in about 3 years, so better buy with long warranty.
To get mattress out the cabover, I used 2 ratchet straps to bend it about 150 degrees in the center and that pulled it out the passage.
Once you have it standing on its side on the floor, you can slide it via door.