I have been using a costco table(lifetime brand?) that seems pretty tough and was only about 20 bucks. Way tougher and cheaper than the wally table I destroyed during stress testing, and then returned of course. Has been plenty strong for one rower or two passengers, even walking or standing on it.
The costco table seems a little heavy however and I am needing to make another and possibly a beaver board. Wondering if I need to use 3/4 inch plywood or if 5/8 would be strong enough. Not sure if weight and money savings would be a wash...
I think the best option is a plywood table/deck/backboard with strap slots/handles cut into it, leg flanges screwed on, with a drop bag(45$ frontierplay for the cheapest) underneath where you can put the legs, chairs, pump, etc. Sand and paint/coat table of course. I like white or light grey for low solar gain.
Like people have said, totally custom design to best cover your frame bay/drop bag and suit your needs.