Keep in mind the diesel motorhomes use many of the same components and drivetrain of trucks designed for fleet service. So even if you have to go to an older than 2010 unit to find a really good MH in your price range you'll get a long life out of it.
Your best bet is to spend time in the MHs for sale in your area and look for the quality and floorplan you like, have a list of at least 3 you liked. Do some internet research to see what the owners have said about the quality of units from the manufacturer(s). Then due a nationwide search to find a good deal on the MH you like.
Like boats you can have an RV inspected by a professional before you buy it and transported to you even if it's across the country.