I know the US is a litigious country, but I just don't see the mileage in suing a business that has trivial assets (a few animals and huts, and some hand-tools) operating on rented ground. And once you had about three satisfied customers the clients would be climbing over each other to attend and will be able to afford insurance. The one time I got sued by a stranger it was when I was driving an expensive new car with Swiss numberplates, and had just moved into a big house (by local standards 1400 sq ft is huge!) Someone pretended to have slipped on ice on my path, while crossing my property to get access to the house behind (which they can do). Once they found out they house was rented and I didn't have insurance they lost all interest, and since then I blend in better because I know the local customs and have numberplates showing me to be from this town.
For a project like this, you can market it any way you like. It is really a holiday camp or hotel/hostel with a theme, that's all. If you rent a house with the land it just looks like you have guests who help out, especially if you can find somewhere a bit out of sight with some sort of natural barrier like a hill or trees to discourage the curious. No one likes to be gawped at when they are very overweight and dripping with sweat outdoors.
If you want to do this you should get started right away and start looking for cheap land to rent, and get a website up. You can't overplan these things as a lot of the practicalities are only apparent once you are up and running.