Here's the deal - I have a 2002 Foretravel with 185,000 miles on it. It cost more than my house when it was built and I bought it used 10 Years ago this month at a very depreciated value. It is extremely well built and the chassis should last for 500,000 miles. But being 20+ years old, it does require maintenance and renovation, just like a house requires new appliances, carpet, paint, roof, etc. Some cosmetic, some required to keep things working. I'd budget $10K for the first year after purchase and another $1K/year for upkeep on the house part of the coach. That doesn't get you a major refresh.
And chassis maintenance and repairs are expensive. The more you can do yourself, the easier on your wallet. Basic parts for engine and generator LOF, air dryer, etc. is probably $300-$500/year. If a shop does it, you're probably at at least $130/hr or more. I can do the basics in my driveway in about 4 hours. I'd budget $2-3K year for chassis upkeep. Tires are $500/each, batteries are expensive but will last if maintained. It cost me almost $3K to replace 3 house and 3 chassis batteries.
We really love the life style and options the motorhome affords us. We plan to keep putting on about 10,000 miles/year as long as I can keep up the maintenance. Then it will be time to look at other options.
Look for one that is well maintained and renovated and pay top dollar or look for one that is well maintained and not renovated and discount it. You can then live with the dated interior or renovate the way you like it.
Rich