Not sure exactly what you have, but paneling all the odd surfaces on boats is expensive and time consuming.... probably why Bene did it that way.
Many have a vinyl backed by thin foam, maybe that's what you have. It seems to be the best solution unless you want to be a boat builder
. The inside surface of a boat
has many lumps and bumps, the foam backed material hides much of this. Just painting will likely be pretty ugly as well as may require a bunch of grinding first which will put itchy fiberglass
dust everywhere in the boat.
"Rat fur" is used in lieu of vinyl on some boats. You spray contact cement on the surface and apply the thin material to the hull
with either product. Then cut the excess away with a razor knife and replace the wood trim you took off to cover the edges. If no trim then just cut it all to join together. you now have a fuzzy furry interior! haha
Bottom lione is there is no easy way to make it look like the main cabin