Ronnelly,
We too tried a foam pad, but it was still uncomfortable for Pat, as she had a spinal fusion years ago.
Isoform mattress is sold factory direct. They ship common carrier fully expanded, unlike Costco, which is folded and compressed into a smaller box.
Our Montana 2955RL has the short queen and Bergad will make the matress to size,along with the cover. I had considered cutting down a queen when my wife pointed that the cover would then be to big.
The link is
www.isoform.com/
We purchased the 8 inch as that was about the height of the facory matress. As for the house, we thought bigger might be better. The 10 inch it was explained is a little softer than the 8 inch.
PatnRich
'04 2955RL, 04 GMC 2500DA, 16KPullrite Superglide