Good questions. I'll be interested to know what you find out overall. Tires
, of course, depend on how many miles you travel, type of roads, and care. That will be pretty much like your tow vehicle, I would think.
I don't know how much traveling my '89 has done over the course of it's life as I only purchased it this year. From the looks of it, it was well used but not necessarily abused. However, all of the equipment you mentioned, except for the tires
(and probably bearings although we opted to repack rather than replace as they were in good condition), is original.