Got a bit further today.
Masked off my electrical and tacked some rubber material to the wheel well to use as a backer for the fiberglass. IDK just thought it sounded like a good idea. If it wants to vibrate at least it wont be fiberglass to metal.
Than taped up some fiberglass mesh and started to coat it.
Than I fit the mdf back in to see where I needed to overlap the mesh to attach to the box.
Than coated the rest up to the mdf from inside.
This part just seems ghetto and may look that way as well, but I didn't know what else to do. I will add a few more layers of resin to thicken it up before I attempt to pull it out after it dries. This is turning into a bigger project than I imagined....