We worked with the dealer to refund us for the unused mattress. It was unusable and felt like it was made of old beer cans. I think that batch must have been sent back from Guantanamo Bay because prisoners sleeping on them would have had grounds for "Cruel and Unusual Punishment."
We bought something called "Bed in a Box." Memory foam mattress that came all compressed in a big 100# box. I wrestled it into the MH and unwrapped it (cut through the duffel bag and shrink-wrap stuff) and placed the mattress on the platform (instructions say to place on platform or slats across box springs. In about 3 hours, it had expanded to a 13" thick mattress with cover already affixed. We added a mattress cover.
My wife suffers with Fibromyalgia and on our maiden voyage, she slept on the mattress every night with nary a complaint.
It's an "RV Queen" size that is 2" shorter than a regular Queen but a regular Queen would have been too long. Only drawback is lack of access to the nightstand compartment since the mattress is so thick. The little headboard could be removed but it isn't a major concern.
These mattresses are great and I recommend them to anyone who might have concerns about bedding.