Awesome concept.
Rule wise, one class makes sense. Maybe two tops. Different vehicles will have different advantages depending on the course layout. Limit tire size to 32", limit weight to 1800 lbs, and require 4x4/transfer case as well as a powersports drivetrain combination. No need to have mini 4400 buggies on course with us. Outside of that, just standard safety stuff. But understand that the more stuff you require, the less people will be eligible. If you require solid non opening doors, that knocks out 99.999% of UTV owners, including both of our KOH cars.
Having ten classes for every possible scenario would mean less populated classes, and that tends to keep people away. If you do two classes, make it based on tire size. Anything up to 27.5", and anything 28" to 32". Or similar. To be fair, anyone on 25.5's will have a hard time doing the same line as a guy running 31's.
Entry fees should be low to keep people interested. Courses should not have guaranteed damage, but should be difficult. Upper Helldorado's gatekeeper is doable in a UTV, but almost always destroys the right side plastics. So nothing like this.
