If I were buying a 90s Class A, I would get an Alumalite/Holiday Rambler every day of the week and twice on Sunday. This is the era where they had really perfected RVs and before Monaco bought the company (1999 I think).
They use an aluminum skin with aluminum studs and laminated/bonded foam as insulation and structure. If a wooden-stick built RV gets a leak, it could be ages until you find it. By then the wood is soaked, started to rot, will continue to rot, and grow all kinds of fungi. Many people shy away because of the two-piece aluminum roof, but it has a single seam down the center with a slight curve to the roof. My 1992 never leaked... at least not the roof. The bolt that held the lower awning arm into the skin got a leak and I had a soft spot in the floor which was easily fixed. The nice thing is, if you get a leak (and all RVs will leak eventually), you know that the structure of the RV can't rot if it's aluminum. It's always worth fixing.
My 1992 Holiday Rambler TT spent the first 10 years of its life owned by a couple who parked it near a lake. I bought it in 2002 for $9800 and towed it cross country twice. Then around 2004 I took it to a lake and parked it. I never covered it, babied it, or did anything other than winterize and kept some paraformaldehyde packets opened for the winter. Last summer I decided to upgrade so I bought a 5th wheel to park there and I was able to trade my camper for 8 acres of land and a used 4-wheeler. That sounds like a whopper deal, but the land is kinda useless. I think the non-running 4 wheeler was the better part of that deal.
I personally don't prefer rubber roofs. They require maintenance. The UV damages the rubber, so you have to get up there and scrub it with a special cleaner, then treat it to protect it. Then for the rest of the year, the slowly-oxidizing rubber drips gray streaks all down the sides of your RV. I always felt that the increased sealing you get from rubber is more than offset by the once-a-year walking around on the roof and the extra maintenance. I would say whatever roof you choose, get one with the least number of seams, and as Toyman ever so brilliantly pointed out, get one that that cap wraps down over the sides.
When looking at a potential RV, look hard at the cabinetry and floor coverings. In an effort to keep weight low, most RVs make hideously awful cabinets that are a corner piece of 1x1 pine with luan stapled to it and covered with a vinyl sticker to look like wood. While the cabinets may last just fine, I have never encountered an RV where this wasn't an indicator of cheap, lightweight construction everywhere else. The cabinets in my Holiday Rambler were a similar construction, but they made stressed-skin platforms out of that 1x and luan, so it was skinned inside and out. Still light weight, but super rigid and looked very nice. I had no problems stuffing those cabinets full of canned goods and dishes and driving on Missouri roads. (sorry, MO, but your roads suck).
Look at the hinges and grab the cabinet doors and check for hinge flex. See how the doors line up. All old RVs in this era will likely have awful plastic bathroom and kitchen faucets, but they follow standard sizing, so its easy to get a nice residential version of both and change them out. Toilets will be pretty standard Dometic units that work fine. They'll either be a side flush or a foot flush and both should serve you well. If you don't like them, the aftermarket has some nice upgrades. If you plan on frequently using it for family trips with 6 people, consider a macerating toilet. If it's just going to be one or two trips a year, don't worry about it. When you hook up to sewer, always let the black tank almost fill up before dumping. You can leave the gray tank open, but if you leave the black tank open, the solids make a poo mountain and the liquids drain out. Letting it fill allows time for the solids to liquefy, and any solids that remain will get flushed through by all the liquids.
90% of the RVs out there will have a standard complement of appliances; dometic LP range, 2 or 3-way fridge, and a gas water heater in either 6 or 10 gallon. If you get lucky, you'll get the best of the best water heaters which has both gas and electric. Great for having 6 people showering. The electric will maintain hot water without using up your LP, and you can supplement with LP if you're all showering every day.
Unless you're going really big (as in two rooftop AC units and washer/dryer), a standard 30-amp 120v plug will be sufficient. 30A will run most electric water heaters, A/C units, and still have some left over for a TV and lights.
I also like to keep a cube heater around. On chilly nights it can pretty easily heat the RV without using the furnace. Basically, I'm saying to take advantage of the electric utility included in your campsite whenever possible. Most LP appliances in RVs are grossly inefficient and they use up propane quickly.
Since you're looking for a motorhome, don't neglect the chassis and drivetrain. Many are built on the P30 (GM step van, often called the Workhorse chassis) and they are a bit stressed. You'll find yourself potentially having white knuckles every time you're passed by a truck. John Deere is the other big chassis manufacturer. They sold to Oshkosh and Freightliner for their step van trucks and they are a much beefier option. John Deere chassis often came with Ford running gear like the 460 or the 6.8L V10/E4OD or 4R100. Workhorse almost always has Chevy running gear like a 454/4L80E. Either one of those engines/transmissions is wonderful, but try for the John Deere chassis if you can. If you go to a diesel pusher (not as likely in your price range), you'll have to consult others on that. I know they borrowed heavily from Blue Bird, Gillig, and Thomas bus chassis so they should be up to the task.
