The beautiful state of Wisconsin has 117 roads designated as “Rustic” they are a mix of paved, gravel and even stream crossings. Do 10 and get a patch 25 and a certificate from the state.
So far I have 17 and the patch. RR51 is gravel and requires 4 stream crossings, RR91 is mostly gravel with deep ruts and deer.
None of this is a problem for Endeavor trikes as they are designed just for this type of riding. Standard motorcycles and trikes would find it difficult to impossible.