You said you're looking at used Newmars and Tiffins for $225k. Have you priced what a new one of those manufacturers and models cost? There are other manufacturers out there for much less but you're looking at quality RVs. We bought our Newmar Dutch Star in 2004 for $150k - new. We wouldn't buy one nowadays for the price they're getting.
I don't know about Tiffin but Newmars can be ordered with many individualized additions which ups the price. We made over 100 changes to ours.
Take a look at this site for comparison prices and years:
http://motorhomesoftexas.com/c#/coachesrv/all/default/all/all/all