Nailpolish remover is acetone with a fragrant oil thrown in. Not good for prepping gel coat. VERY flammible and toxic.
FWIW, I wrote an article about the various kinds of fiberglassing products available for boatbuilders. Most will be applicable to cute glass trailers.
It is rather opinionated.
Be careful about mixing epoxy resin with a polyester resin structure-- which is probably what most trailers are. You can do it, but the prep is a beast. Epoxy resin is more of a yellow color.
I ramble on.:r