How does the Alucab mattress compare to the 23Zero you had? I had a 23Zero and loved it, except the setup and tear down. Bought a Autohome and it was marvelously comfortable, but I'm switching to a aluminum body to mount an awning and accessories to; leaning to Bush Co. or the Alucab, but mattress is a main concern for me since I have to deal with lovely back pain.
Mattresses are consumable items to me and they can be replaced easily so let that sway your decisions for a RTT. They all pretty crappy from the factory, hard density with little to no "resiliency". Just head over to your local foam and fabric supply shop and try out various foams for your exact body type and health issues.