Totaled my fifth wheel, how to work with insurance adjuster

The prices you see aren't necessarily the selling prices - sellers ask what they hope for, usually with the expectation of bargaining down to what they'll actually take. So, he may not be wrong in offering less than the asking prices you see. Depends on how much, and how strong the market is.

But yes, talk to your agent about it - don't just rely on the claims adjuster.