I've been impressed with the Thermarest SoLite foam sleeping pads that I put in my Autana. I taped them down to the floor between the floor and mattress. I used to get steady water droplets under the mattress every night but since putting those pads in I've seen ZERO moisture under the mattress. Completely dry. Also, these are firm backpacking sleeping pads so they complement the foam soft mattress really well. Also, one side of the pad is reflective which I put on the metal floor side and this definitely insulates quite a bit. This all comes from a pad that is .6" thick and less than a pound so you don't have to remove bedding, sleeping bags, etc. takes up no space.
Excellent! Thanks for the tip. You don't have the anti-condensation mat at all then, right?