When I bought our boat the PO had done something along the lines as your thinking. I wound up pulling out almost 30 pounds of damp plywood. If your going to do anything make sure the wood is sealed and as light weight as possible. Cargo nets sound good. I use it for aft anchor storage and have that strapped to the aft cabin wall and the rest of the stuff is all soft, floats and toys. We only use the boat on weekends and short vacations so you might want o sort that storage area out.
I have a much better idea
Look up a company called. Weldmount
They make really cool fasteners which come with super high strength epoxy which is meant to very permanently bond to Fiberglas
The fasteners are threaded studs, or female threaded posts.
With these, you can then attach starboard strips, to which you can secure your nets, etc.
So, you can randomly attach these wherever you want. You could actually attach shock cords directly to them as well
You can buy Weldmount kits which have neat assortments. Look on eBay for these
You will be impressed