I bought a tiny camera that hooks up to the computer with a 25 foot cord - about $25. on Ebay. It's not "all that", but there have been many times it would have been better than a flashlight and inspection mirror. Caution: Good luck figuring which way is up.
The dashboard complaint isn't new, although I think manufacturers are making them better today. People don't realize the amount of flexing the front cap has - or that the windshield is "structural". It sounds like they used foam as a structural component. I'd brace and "Maxbond" (or some other modern cintruction adhesive" to make it better. Your tabbing idea is good, but getting the best areas prepped might prove impossible.
Your fiberglass repair MIGHT be the strongest part of the RV. I'd also look for signs of the windhield moving - and indication that the metal "cage" framework (if there is one!)behind the cap hasn't rusted apart or been damaged. Perhaps someone who hass seen the same model after an accident will have some input as to what's behind your cap.