We paid $14,000 for our 1998 Four Winds 23rk with 36,000 miles on a Ford E-350 chassis with a V10. It was in excellent shape with new tires. It did not have any maintenance records. So I dropped another 5K into it replacing all the hoses, engine flush, radiator flush, leaky rear pinion seal, cleaned and replaced 15 year old rear end oil. Replaced tie rod ends, changed caster to +5 with new caster sleeves, front break line hoses, mass air flow sensor cleaned, Safe-T-plus steering stabilizer, extended hardline tire air valves, new ADA ceramic toilet 22 inches high, replaced all the interior lights with LED's, new do everything radio in dash, Amp-L-Charge under the hood. Transmission oil was fine, changed engine oil to synthetic. Next is to install simulated rims to make airing up easier now that the valves are all extended. Took a 2500 mile trip this summer and averaged 13 mpg.
So, if you are buying a used unit, understand there can be things wrong you don't know about, and be prepared to spend more money. Other than a steering problem I knew about before I bought our MH, and understood how to fix it, every thing worked fine. I just decided to invest the money, I will most likely, never get back out of it, but also will not be sitting on the side of the road because of a hose, tire, or some other maintenance not fully taken care of. I went on a 300 mile trip before I did the maintenance and it work then also, but a 70, I am not going to be crawling under it on the side of the road. Some of the maintenance I did, a lot of it I had done by a reputable garage. I also changed out the converter to a three stage from a single stage converter. I can now leave the MH plugged in all winter long in the garage, and the Amp-L-chager will keep the chassis battery charged, while the house battery is kept up by the new three stage converter.