[cwl1979]

If your coach is registered to a business, and used in any way for that business, you actually need at least a class B( or whatever it is in your state that allows straight trucks over 26K). If you pull a trailer with it of any kind also in use of your business you will need a class A license. As well as current DOT medical cards and loads of insurance. This holds true for ALL states.
You will also not be allowed into California and they would turn you around or have it towed out from the weigh station.
When I purchased my coach I knew i was never going to be able to visit California in it. Mostly due to their dumb speed limit for 3 axle (or more) vehicles. I've driven commercially through California and can say those guys don't play and ignorance is not acceptable. Even with an Alaska license. They did not appreciate me doing 65 down the grapevine laughing because they thought that was steep.
If you wanna chance a trip into California i would recommend not having it registered to a business. At a minimum though you would need a DOT number and the words NOT FOR HIRE PRIVATE COACH clearly displayed.
I haven't looked but I'm sure permits are available for purchase that will make you legal for a weekend at the beach.