My damage came from another driver who side-swiped our trailer with this rear-view mirror. We were fortunate that it put a 6" X 24" gash through the outer wall but didn't extend to the inner wall. No internal structural components were damaged. So this was basically just a penetration/scrape of the outer fiberglass wall. The flat tire came from his knocking off the TST TPMS sensor; the system works and the sensor was easily replaced. Praise God this didn't impact the fuel station or fuel tanks. He did take the bottom rung of the side-mounted ladder; I just cut that bottom rung off and use a step stool to get to the next rung up. Perfect repair? Not by any stretch of the imagination. But by being flexible in my expectations, I save thousands of dollars and more importantly didn't have to relinquish my trailer to repair shops for several weeks!
I emailed photos to two different fiberglass shops and they gave me estimates of $4,000 to $5,000 for this repair! I couldn't believe it - either they didn't really want the work or they were concerned that I would be picky about the final work. They both stated the biggest cost was matching the paint and that they would have to paint and redo the graphics on the entire side panel.
This ended up being on my dime - the police refused to cite the other driver. I could have let my insurance handle the repair but it would have taken weeks to accomplish and I would undoubtedly see an increase in my insurance costs.
So, I purchased some fiberglass repair materials (glass, bondo, etc.), sanded the area down, patched it, sanded it, and painted it - cost about $100 for materials and a week of my time. Lots of "how to" videos on YouTube. For paint I could not find a direct match, so I cut straight lines that sort of integrated the repair in with the graphics. If you look close, it looks like it was done by a disinterested 15 year old - I'm definitely NOT a fiberglass repair guy. But if you didn't know about it, I bet most people would walk by and not even notice it.
I still have a couple of rounds of sanding and then final paint to go - I think I can find a better match on the "grey" paint. Here's how I left it so we could go on a recent trip. I can't advise you on your rig, but if there was no structural damage, the outside CAN be repaired without a lot of expense. I actually kind of enjoyed this new experience and gained some skill and tools in the process.
Hope this helps.