Been on all of the trails closest to the parking lot (15, School bus, Rail Trail, Rattle Rock, Stairsteps, 39, etc). I see there are more black "difficult" trails in the North/East section of the park, but never see any videos or pics of those trails. Anyone have experience riding those trails and are they worth the hour long trip to get there (9, 10, 12, 28,29,31, 8, 23) ??