Do it like LeMons, tires, brakes, safety equipment is exempt. It's one way to have fun, cheap, safe rallying. Race series are always trying to reduce speeds anymore do to the danger.
The difficulty is then in finding good stages within the US. Logging roads are a good start - but they're usually either unmaintained (during growth cycles) or busy as hell (during harvest cycles).
Fire roads are another possibility, but they tend to be on public land where officials would likely not give permission (for any sane amount of money).
Desert stages would be easy because plenty of it is owned by private organizations and people - but that's geographically limited.