I think in general, the WDW resorts have hard beds. If that's what you want, you'll be fine booking any WDW resort. Of the resorts we've stayed at, BCV seems to have the hardest beds, but we haven't stayed at all of them! My DH has a bad back too, and I have joint pain, and I have to say we pretty much hate the WDW mattresses. We are DVC members, so we put up with them.