Buy a MH in California and no worries about the emissions requirements. In general in California the emissions allowed varies by age of the vehicle so it will be less stringent on a 20-year old MH than a new one. You can check with the DMV at their website and learn the specifics.
Motorhome prices are a function of age and not mileage. In a lot of ways it would be better to buy a 20 year old motorhome and have a mechanic go through it replacing hoses and belts and brakes and tires and having a reliable vehicle when you are done.
Certain engines have been less reliable than others and the owner specific forums for different coaches will provide good information on particular makes and their engines that are now giving their owners grief and which ones are relatively troublefree and easier to maintain and repair.
