As a Revcon owner for 12 years and over 80K miles, I can probably tell you anything you ever want to know. Revcon built by far the best handling motorhome ever conceived. Most of the time I drive with 2 fingers on the wheel, even at high speeds. I've seen 98 mph on the GPS 3 times, twice towing my Grand Cherokee. Aircraft Aluminum shell and framing, honeycomb hollow core cabinetry with Wilsonart formed over the frames makes for a very light weight, low center of gravity coach. Traveling over 70 mph, in an emergency maneuver, I have turned a quick left and a very hard swerve right with no ill handling fears. I yanked the wheel so hard turning back, I pulled a muscle in my back. The front end slid some, but no loss of control.
As far as the interior goes, because of the Wilsonart laminate on all the interior walls and cabinetry, the interior looks the same as it did when it left the showroom. The upholstery and carpet will wear, but the cabinetry is scratch and chip free. Between that and solid wood framing, the interior has stood up well in the less than ideal environment of camping. The interior walls are plastic coated aluminum, which of course does not rot. No need to worry about seams leaking, they won't.
As far as the drivetrain, once you hit '79 or '80, the drivetrain was custom configured, built mostly with off the shelf parts. Some of those part were customized, but all your wear parts can be purchased form NAPA or any other auto parts store. You asked about brakes and mountains. Revcon brakes are not the best, however there is an easy turn key conversion to disk brakes which makes an incredible difference in stopping. I converted mine 2 years ago. While it won't stop as good as my Cooper, for a motorhome, it stops extremely well. Very light pedal touch, easy to control. There is only one drivetrain issue that needs to be managed with a Revcon. Revcon used a Dana 70 running in reverse for the differential. This changes the stress on the diff, and causes it to wear faster than normal. The typical life expectancy for a Revcon diff is around 70K miles. There is a solution. With my high power mods with the 502 conversion, I did some research and found an engineer who has modified Dana's for high stress environments. We added bearing girdles to stabilise the bearings, so they do not walk under stress. This includes a very thick plate cover which also helps. Tru-loc carries is much stronger than OEM, which prevents the wear in the ring side bearing sleeve. Pretty good indication that this will survive the test of time. Not all that bad price wise for the mod.
As far as purchasing one, your main expense will be relative to the condition of the front suspension. Any time you have front wheel drive, the parts are bigger and therefore cost more money. They don't necessarily wear out faster, but just cost more to replace. So if your shopping, the condition of the front suspension should be a big factor in how much you pay. You are checking for looseness in the steering, tie rods, a-frame bushings, ball joints, bellcranks - parts that are considered wear parts that would be worn on any 25 year old coach.
Revcon is a very well built coach. I like the idea of fixing stuff once and not having to come back to it later because of a poor design. Once you get into it, you begin to realize how well done they really are. There is a group of us on Yahoo - Revcon_Curious, as well as a privately owned forum here:
Revcon Forums • Index page
Have a look around to get a sense of what you are looking at. There is a ton of tech smarts over the whole group and many willing to help.