To fully research your product choice regarding service availability, find a driver that has a product in use now and ask if you can borrow his (her) product ID numbers (serial number, model number, whatever). Then go to the manufacturer's web site and pick a half dozen service locations at random. Make up a straightforward problem (generator won't start, will heat but won't cool, seems to be smoking more than normal), and call the service providers with your situation. Note how you are treated. Could you get through after hours? How soon could they get you in? Were they willing to make your problem their own?
It might be wise to talk with some RV drivers too. They are heating/cooling/powering a lot more space and things than most trucks require. What do they use and why? Where do they go for service? What kind of luck have they had with their products of choice?