67 runs between Doe & Iron Mtns. You can see the Stone Mtn. trails from 167, which runs between Stone & Doe.
I'm not sure which trails you saw from 67, but there is a lot of logging all the time up here, so there are trails everywhere. The tricky part is finding large tracts that all connect.
Btw, 167 & 67 meet in Butler, TN. I heard that the Doe Mtn. trails might eventually reach that intersection. That area is supposed to be very steep & technical, so I don't know if there will ever be an access point to the trails there or not, but it gives you an idea of the size of the mountain. The North end is right behind the shopping center with the Hardees, which "may" become an access point for gas & food.
There is an access point from a campground on Mining Town Rd, off 167.
A buddy & I hauled the ATVs & chainsaw to Stone Saturday. We opened a couple very steep long trails and discovered a few that I hadn't ridden before. They weren't rocky, but will still be quite a challenge on motos. I rode Sunday and my d/s tires didn't have a chance on those hills.