I got the evil look when registering the 5 ton here in N Ca. You can register it Historic at $81.00 a year, but you can never haul anything and you are supposed to use for events only. You can register commercial, but make sure to look into all that is required (BIT program, smog, etc) in addition to the annual fees. I drive mine at least once a month and have never been stopped, but never hauled anything. Insurance for us is $800.00 per year commercial policy with a mileage radius limit of 50 miles.
As others said, you're going to need a big area and big tools to do service or repairs.
I had a business in Newport Beach in the '80s. Good luck.