I parked at 660m as I was borrowing my brother's truck and didn't want to push it. The road is pretty degraded but I suppose you could drive if you were really motivated. The road gets narrow and very rocky, there are only a couple very small pullouts. After the Joan/Curran split sign the trail is single track. Quads and dirt bikes would have no problem. Shaun C previous report has good photos of the tougher sections, it still looked the same.

This old road is still driveable in 4x4 HC to the Mount Joan/Curran trailhead. Narrow & rough with some medium sized rocks & one short slightly off-camber section. Nowhere to turn around or park until the end as drawn here, impassable beyond except to maybe dirt bikes or quads who may be able to get to the next old junction where the hiking trails split