Models or brands really don't mean much in the RV industry. For the most part, all 5th wheels and travel trailers are built of the same materials using the same procedures. They have pretty much the same appliances and construction. The best thing is to find a floor plan that fits your needs, and then have an RV expert look it over to check the condition of the unit. Water is the number one enemy of an RV, and hidden water damage can rear its ugly head later on down the road.
Your living quarters horse trailer is built 300% better than a typical RV. Most trailers use light materials on a flimsy frame in order to keep weight down. They will not last nearly as long as your all-aluminum horse trailer.
I would not plan on being able to purchase one used RV and having it last the rest of your retired life. In reality, especially if full-timing, you will need to replace the RV every 5 to 7 years. The exception to this rule is to purchase a new rig, and store it indoors when not in use (that's what I do... my travel trailer does not sit outside unless we are using it). Of course, this won't work for long term/full time use.
I have been in the RV business for 25 years. They are called recreational vehicles for a reason: they are designed for solely recreational use. As long as you have realistic expectations, you will have a blast. However, I have experience with way too many customers who can't understand why they aren't built to last. The real reason? Most folks wouldn't be able to afford a properly built rig, and most folks wouldn't have a big enough truck to tow a properly built rig because it would be too heavy.
Yes, slide rooms can leak, yes, slide room motors can fail and leave you stranded. I would avoid any RV that uses a Schwintek "in-wall" slideout system. Hydraulic slide outs are best, followed next by the standard "through frame" systems that use a motor underneath the slide, followed third by the cable operated slides. Schwinteks are finicky and don't like to work if things aren't square (which is often in the case of an RV).
When shopping for a used RV, there are two things I always recommend:
1. Make sure the fridge works. A typical RV fridge can cost between $1800 to $3900 (depending on the model). So a bad fridge can turn a "good deal" into a bad deal pretty quickly.
2. Inspect thoroughly for water leaks. If you find soft spots in the ceiling, walls, or floors, walk away. It's very expensive to repair water damage, and the damage you see typically means there is a lot more damage you can't see.
If you can find a trailer that is built like your horse trailer, that would be the best solution!
I still love camping and RVing, but I want people to have realistic expectations when shopping for a rig.
I hope this helps.
Casey
1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter