I have an older fiberglass blind that I believe is either a Texas Deer Stand or Superior Supply “six shooter” 4x6 blind. I’m about to redo the carpet on the floors and carpet the lower walls. It has one shelf under the long window that’s rotted on top (wood brackets are still fine) that I’m replacing as well this weekend. My question I need help with is ideas to mount addition shelves inside. Not sure it’s a good idea to screw anything, don’t want to drill holes for bolts and I’m not sure a glue or epoxy would hold a piece of wood through the Texas heat this summer. Any and all ideas are welcome! Pic below to reference what I have. Unfortunately no interior pics right now.

Drill thru the wall, screw head outside, seal under heads with premium caulk outside, tighten screws, clean excess caulk away, sand and prep exterior and use quality fiberglass cloth and resin over screw heads, drink a few beers and then touch up paint

/done

Appreciate the suggestion.