Depends on your personal preference to firmness and support. We had a futon mattress in out Weekend Warrior that was just fine. Our Arctic Fox had a pillow top foam mattress, but the density was too soft and we added a layer of memory foam under the mattress to keep from feeling the base. Our Host has slightly more dense foam, but we added the memory foam to it before ever trying it as is.
Host Mammoth 11.5 on Ram 5500 HD