This is going to sound apocalyptic, but I wouldn't buy an RV manufactured after about 1999. Starting in about 1996 there was a big mix n match of RV manufacturers. It was like their internal stock market crashed. This was also around the time that RVs started becoming lighter in response to the overwhelming number of CUVs and small SUVs that people were favoring. Prior to that era, full size, RWD vehicles were ubiquitous and easily found, gas was relatively cheap, and RVs didn't need to be light. Beginning with OBD2, cars started being folded tin foil (unibody) construction almost exclusively FWD unless you bought a big American truck or SUV. Transmissions went from beefy 3 and 4 speed autos that held together at the expense of sapping fuel to super-complex 10-speed autos with more computer power than the laptop I'm typing on now.
I began my full-time RVing in a 1978 Road Cruiser Land Yacht 5th wheel. It was heavy, but it was a steel I-beam frame with steel studs. It probably logged 4 years of 100k miles and daily use. I finally sold it to a guy to use as a hunting camp because the water system needed multiple repairs with parts that were obsolete. I then had a 1993 Fleetwood Wilderness TT. Rock solid. I traded that for a 2000 Fleetwood Wilderness that didn't stand a chance. The walls on either side of the slide room were buckling and the paneling was breaking, the slide would never go in/out correctly, the roof leaked, and the siding delaminated. Within one year, the carpet had worn through to the backing in front of the door, most of the hinges had failed on the cabinets, and the structure of the whole thing settled bad enough that the doors wouldn't close (or latch depending on the settling).
I sold that one and bought a 1992 Holiday Rambler TT in 2003. That was my full time residence for three months a year up until 2019. 16 years and never had a single failure except one small leak where the bolt holds on the lower awning bracket on the side, so it just leaked into the belly. Fixed it with 30 cents of silicone and 2.318 minutes.
Mom and dad's current Forrest River TT is a 2018. The cabinets are a joke. The hinges are the thinnest stamped steel and they have all failed. The vinyl on the couch is so thin it feels like a trash bag. The tires are the cheapest junk and he had three (yes three) tires blow on a 250 mile trip. When the one tire blew, we discovered that the wheel wells were made of luan, because tire shrapnel blew through the luan, through the padding of the couch, and blasted a hole in the vinyl like you had shot it with a shotgun. The repair required 4 months and a complete stripping of the interior... and they still have a cardboard camper.
Sometime go to an RV show on the last day. I have seen brand new RVs with sagging cabinet hinges, separated laminate on cabinets, and wallpaper peeling off the paneling after three days of some visitors walking through. Heck, I have seen them on the first day with cabinet doors that fell off on the way from the dealer to the show. The level of cardboardness in RVs today is just insane.
1930s - 1995, RVs were made to last with obvious decline toward the end
1996 - 2003, RVs were made for the modern camper - three weekends a year until they lose interest after two years
2003 - today, most RVs are a cardboard box that won't last the first weekend without a massive failure.
My current RV is a Sportsmen 5th wheel from 1992. It has lived a full life, visited at least 20 states and probably has 50k miles on the chassis. Mom and dad bought it used and abused it for 25 years for at least two months a year, it looks practically new, everything works, and I expect another 10-15 years from it. It has been parked on my lot in Canada without my being able to access it for three years, but my buddy has been keeping an eye on it and he says it's ship-shape. Edit... I will say that the fridge died. It had a leak which could have easily been fixed for a couple hundred dollars, but I opted to buy a residential 120v fridge instead since this is now permanently parked.
I'm in the market for another small TT, and I would rather have a TT from the 70s than anything from the 00s-up