The Federal Government actually owns most of the west. Its the reason why there's more land for public recreation and national parks in that region of the country.
You can typically hike, camp, or explore BLM land, which is the majority of it, as much as you want so long as you don't start any fires or litter.
Autobrewery syndrome is rare and probably has more to do with your diet and antibiotic use than consuming a few actively fermenting drinks.
Some drinks like pulque are traditionally drunk that way and that's why they can't be shipped long distances. So if its been done by other cultures for thousands if years, I'm not a doctor, but I'm gonna wager its fairly safe.