Do Not Start with an RV!
Look for a good enclosed car hauler. The strength is unrivaled and the extra width (8.5') is really nice inside.
I have already done one 28' bumper pull and will be starting a 40' gooseneck soon. The car hauler trailer will last 30+ years if well cared for, and you can get a used one without breaking the bank. Just avoid the cheap "hurricane cargo" or almost anything else built in Georgia. Stick with Haulmark, Wells Cargo, or another top builder.
I bought the 28' for $3k, put $10k into converting it into a toy hauler, and was just offered $14k for it. No, not really much of a profit after adding up the hundreds of hours labor, but better than taking a loss like on any RV.
Things to pay attention to when looking for a trailer:
Interior height: most are 6' or 6.5'. That sounds great, until you have to add water tanks and other storage. try to get a 7' or taller. I like 8' so I can build a sub floor 1.5' tall and have full pass-through storage and room for a genny, propane, and water tanks underneath.
Weight and axle location: Car hauler frames (including walls and roof)are usually steel vs wood and are much stronger and heavier than RV frames. They'll last forever as long as you keep rust away, but they do add weight. They also usually have the axles mounted further back like a toy hauler, so keep the distribution in mind when furnishing.
Doors: Some already have RV entry doors, and I always prefer a rear ramp door rather than side opening doors.
Don't buy all your stuff new! find a salvaged RV and use all you can. I bought a wrecked (unrepairable) 1 yr old Mountain Aire for $2K, and from that got a perfectly good Onan generator, 2 roof AC units, all 3 holding tanks, some plumbing, fridge, stove, oven, microwave, power inverters, wiring, etc. When I was done with it, a scrapper came and removed the carcass for free.
You can use a lot more residential items than you think... While I used an RV toilet, I used a residential shower insert, residential sinks, kitchen counters, etc.
Yes, my 28' bp trailer weighs 10k lbs, my gooseneck will prob be around 18k.... but who cares. Mine will be on the road 20 years after most new RV's are scrapped, and it's designed and laid out exactly how I want it.
I also consider it an advantage that most people have no clue it's an RV. I park and sleep where RV's usually aren't allowed to do so, and for some reason, truckers are more friendly.
If you want a motor home, look at Freightliner box trucks. very affordable, strong, big enough to make a great RV, and actually get better fuel mileage than a dually pulling a trailer the same weight.
Good luck!!!!
