DRICORE DuraDri™ Mattress Underlay for RV’s, Boat’s, Camper’s, and Bed’s Creating Air Flow for a Dry and Comfortable Experience

It’s really the same issue with RV’s and vans. Anything that solves the moisture/venting for those should work for your needs here. Something like this is a simple option https://www.amazon.com/DRICORE-DuraDriTM-Mattress-Comfortable-Experience/dp/B0CNHC5YNF?th=1

Yikes that’s a real project but yeah quite the steal. I would work on the seat too, looks very uncomfortable. I had to add padding to my T50 original seat just to be able to stand it. This stuff along with some yoga mat helped alot