I'm interested in this too... I have a fifth wheel and the fiberglass on the passenger side by the upper master has delaminated. I seen plenty on ppl pumping in resin but rather have a better fix. Where I am looking for info on pealing back the fiber glass, going ahead and replacing the plywood with sealed marine plywood and maybe using contact cement to glue the fiberglass back... I have heard some people talking about this but very limitedly and no writeups on it I could find. I was thinking contact cement instead of resin due to contract cement setups up for 15 mins and u push it together and it's stuck... no need to brace for 24 or 48 hour at least I would think...
2006 Grand Surveyor 240BH
Pullrite Superglide Hitch
2013 Ford F-350 Ultimate Lariat Edition with 6.7 Power Stroke