So my 2017 Class C was damaged by a tree. It put 2 holes through the roof into the coach, and damaged a few other areas. The awning was damaged, coping, skylight, frig vent, minor water damage inside,...
Whether you decide to go for it or pass, (In my younger days I would probably go for it, I got the hands on attitude and skills, but lost it 10 years ago). But don't go with the 20%, counter with 10% or less. Decide your price and walk if you don't get it (throw the deal back in their court and see what they come back with). If your comfortable, play the game. Good Luck.