Unless you plan on driving it non stop, the mileage is not a big issue. Lots of mhs only get a few thousand miles a year on them. That is why there is so many 15 year old mhs with 30 or 40k miles on them. If you only have to fill it up four or five times a year, it hardly becomes an issue. As Gary stated, I would be more worried about buying something 35 years old. Unless it spent its life in Arizona and the frame was good, and the rest had been refurbished recently, I would opt for something late 90s and newer. Better motors, slides, and all around better mhs. I had travel trailers for years. They do the job and many are quite nice, but since going to the class A, I could not go back. Having had two 38 ft mhs as well, I would not go smaller either. The more you plan on using it, the bigger it should be. Cheers.