Roadfood Food Professionals has vendors in CO (the Pro Hot Dog Vendors covers all food vendors). So let me get this straight. Are you turning the skoolie into an ice cream shop OR are you turning the skoolie into living quarters? Because you are not going to do both and pass a health department inspection. Where all are you going to be selling... what states? You will have to pass a health inspecting in the toughest state you will sell in. My suggestion is that you set up to pass inspections in the toughest state you will be selling in. In the Western states that would be California (who has stupid moronic rules) or Texas. You can find links to state food vendor regs online. Fair warning, they do change often that is why I suggest using TX as your base reference. Depending on what you sell, you may need a food mangers license. Mine was fairly cheap ($100... prices will vary depending on the outfit giving the test) and is good in most states and for a few years. Food vending is NOT an easy job. You mention fairs and festivals... I have been told to get a good circuit set up will take a couple of years. Also you have to remember.... promoters LIE about everything. I know a couple of women who make a fantastic Italian ice (they make it their selves as it's too pricey to ship and companies will only ship to a freezer storage site). They also have a commercial kitchen at home (NM). Go to Roadfood... On the Pro Hot Dog Vendors, READ the FAQ at the top of the page (doesn't matter it refers to Hot Dogs, applies to any food vending), Then search The Food Professional Forums (Restaurant and Vendors) for answers and then read A LOT. Most all your questions have already been asked there. They don't like having to answer the same questions over and over. You have to read both forums as we all post in both of them. Roadfood forum is the best place to learn about the food vending business. Beat out any book or "course" you can find anywhere. Get all your permits. If you set up next to us at a festival, we will turn you in if you aren't permitted! and we are far from the only ones. BTW, you generator question has already been asked/answered on Roadfood, so search for it. There are several food vendors working the Denver area that can help you with CO state regulations. s far as I know, I am the only one who "moves" alot (state to state). We started up the food cart in NC March 2009, Moved to NM vending start Aug 2009, Moved to TX, vending start Dec 2009, moved to NM vending start June 2010 (renewed annual city permit and reinspected by HD). We are here until we leave. We had to collect sales tax in each state we sold in (you can do that online). And there's alot more to it that you will simply have to read about on Roadfood and ask.
State Food Regs (and then there are the CITY regulations in some places!