This road needs to be split into 2 sections:

Segment 1: 0-7.5km
Segment 2: 7.5km -13km a.k.a the actual climb to Jesmond Lookout

I drove both segments, 1 was easy as hell, I would suggest taking big bar road and loop down to the west and come back up to start at 7.5km (this is a high speed road 70-80kph easily done. Instead of going from 0 - 7.5km as it is slow going.

2 will REQUIRE 4L. The final 3rd last hairpin to the very top is the only possible sketch corner (sketched me out) as it is a left turn and gets you at the most tilt on this entire road.

Did it in a xterra with +sized tires, and a 2" shackle lift.

I bet you can do this in a subaru forester type deal with good all terrain tires. We ran into one guy who got his motorbike up there no problems (he said he bailed once). If you can drive all the way it is very much worth it.