Hubby and I have always gotten the full pass on our disney cruises for rainforest. It is a room with heated tile loungers (love them), and aromatherapy showers and steam rooms. You wear your swimsuit, as you are with other people. Hubby and I usually to in twice a day, it is that nice.
We have never noticed mildew...one time, the loungers weren't as warm as usual, we notified the staff and they fixed it.