Having shopped for and bought 3 motorhomes, I would agree with some of the previous comments that I would keep looking and pass on this coach. An older coach with a replaced roof with a gasoline engine with 105K miles would not be of interest. That is not to say it could still have many miles left in it if it was properly maintained. However, there are just too many good used motorhomes available to jump on one with many questions.
At the very least I would be wanting to inspect it carefully, insist on proof (maintenance receipts, etc.) of regular oil/filter changes, transmission service, and I would expect to get it for a really low price.