Like the ones shown on the dirt trax Mt Rushmore off road adventure episode.
I have been on every mile of 62 inch trail in the hills now and can’t find them. I am thinking they were actually FS roads. The “trails” I am talking about are “2 SxS wide” flat dirt with sweeping turns and sweeping whoops. Best part is you can run them at high speed vs crawling at 3 MPH over rocks…if I could just find them.
I am not 100% sure, but the part they reference that looks to be right above the silica mines heading West. Those trails have all changed recently to cut down on erosion. Many of the others they are riding appear to me to be Forest Service Roads, not actual 4 digit trails.