That is the steep four wheeler track. You had it nailed on your first set of pics.
I was internetless and didn't pick it up on my phone.
Big is if you can pick up your bike on steep slippery slopes. "Big" bikes get smaller the older I get.
The Square S gate is further south into Garfield County. Near or on CR26.
When I get home to my land use maps, I can shoot you a coordinate.