The road to the Champion Mine's upper trailhead is a sharp turnback if you're driving up the canyon. We'd missed it on the way in, but it's easy to spot on the way back down.
The guidebook says that it's not recommended for vehicles with a high center of gravity. After driving it, there's little choice but to agree. Jaime said he felt a bit topheavy in his Land Cruiser, mostly thanks to the roof-mounted spare tire.
The trail itself isn't all that nasty, but it's not a route I'd want to drive in bad weather, and especially if the surface is snowy or icy. If you go over the edge it's a long way down!