Okay, that's an owie. Darnit!
So, that is fixable, of course, but it's a bit more involved than just a tiny hole or something. Probably not the best thing to tackle for your first repair, unless you are pretty gung ho. You need to first make the structural repair, and then make it look good. You would need to make sure to keep the shape (since it's not just a flat panel).
On the other hand, fiberglass isn't rocket science either, and you will easily be able to make it stronger than it ever was before.
Given that it's not that hard to remove a bench from these campers, I would want to take out that side's rear bench, for better access. You would also want to remove the clearance light
, and the water inlet. Then you would need to peel back the Ensolite and get the adhesive off (I just posted about this in another thread) (if you have Ensolite and adhesive under the benches...)
Hmm, I'm thinking about how I would repair this...I'm working to a deadline right now at my desk, so these are just quick thoughts.
1) If I thought it would be possible to keep the shape this way, I would "realign" the breaks, and tape over it all on the outside to make it as sturdy as possible.
2) If that support seemed sturdy enough, I would grind/sand the inside extending out at least a few inches on all sides past the cracks, then patch from the inside with biaxmat and epoxy resin.
3) Then I would come back to the outside and grind off the damage, then build it up with cloth and/or fairing compound as necessary, then gelcoat or paint
There are alternative ways, but that's what came to mind on first glance. That said, the taped over broken part might not be strong enough to hold up to your sanding/grinding on the inside. Then you would have to come up with something else, like making a female support/mold or something.
I'll be interested to hear what others have to say (or even what comes to my mind when I'm not trying to get something done for a deadline at work!)
Until you can get to it, I would tape over it with 3M 225 tape and plastic.