motor home mpg

Can you guys tell me, if you will, when a person purchases an older motorhome, for example anywhere from a 1997 through a 2004, and you buy it from a pretty reliable owner, have your mechanic go over it from stem to stern, and keep it maintained, what has been your experience and that of other people who have bought older motorhomes, as to what normally breaks down that can give one real headaches and incur big cost? I know that this is a hypothetical question. But, if the opinion is that older motorhomes give all sorts of problems, would appreciate examples of what those problems would be. I have owned older automobiles most of my life and have had very few problems with them for the amount of time I owned them. Never spent even a fraction of what it would have cost to buy a new automobile. Of course, with the umbelievable prices for new motorhomes as opposed to used, this scenario is exponentially enhanced.

Thank You again for your expertise and advice. :h