[wingnut60]

OK. More useless advice...if looking at a Ford 250 diesel, 2 things: look ONLY for a '12-up 6.7L model, much fewer confirmed problems with them. Based on my experience, buying a used '08-'10 6.4L can be an expensive mistake. I exclude '11-up models as that was the first year for the 6.7L and took some recalls/fixes. The other thing, I would suggest you look for a 350 SRW model as it will have 1500lbs more rear axle weight capacity than a comparable 250--you might need that extra capacity at some point in the future. You would probably not notice any ride difference between a 250 and a 350 SRW pickup, so the extra weight rating is a plus with no negatives.

As to buying from a private owner--in the long run, you are just as much at risk with a dealer as with a private seller, the forums are full of complaints from dealer purchases. Most dealers put only the minimum amount of 'refurbishing' time/material needed to make a unit salable. My thoughts would be to decide on 1-3 brands/models that will fit your needs and look long and hard for that model thru all manner of sources. Using RVTrader.com and pplmotorhomes.com will be 2 excellent sources to look at used pricing to get a feel for when a good price shows up.
The search can be fun or exasperating--good luck to you.

What area are you located in?