Welcome to posting on iRV2 and the Newmar Owners forum. In addition to what has been posted, for me, the top 3 things to consider are:
1. floor plan
2. Will the coach carry your stuff and people? In Newmar land this is called NCC (Net Carrying Capacity). There should be a placard somewhere in the coach telling you what the weights are. One can do the math. GVWR-UVW= NCC.
3. Will the coach tow what you want to tow? This is GCWR-GVWR. Also the receiver/hitch weight rating.
Why are these items the most important? For the most part, they can not be changed. Remember, one is purchasing a truck. weight becomes critical to safety and longevity.
Some large expense items that can be remedied are:
1. tires - no older than 10 years, good tread and no sidewall cracks.
2. batteries - if you can have a load test done. Look at the battery installation and tray. It may provide a clue as to how the batteries have been maintained.
3. all recalls done
4. engine, transmission and chassis maintenance (especially fluids) is current and has been consistently done
5. inside the coach look at the entire ceiling to see if there are signs of water.
The rest of the coach is all personal preference. One can make the decision as complicated as one wants to make it.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours