If anyone's interested in an adventurous alternative, I just scouted another detour option that involves some fire roads out of Gorda, which allowed me to (legally and freely) get around the landslide in a day. Because these forums were so helpful in my research, I wanted to post the info in case it could be of help to anyone making plans around the landslide.
The detour broke down into three segments:
1. Willow Creek Road (also: Los Burros Rd 23S01), a fire road just north of Gorda that starts at the Treebones Resort turnoff. ~8 miles
2. South Coast Ridge Road (SCRR), a dirt road that runs the ridge above Big Sur. ~4 miles
3. Salmon Creek Trail (SCT), a half-abandoned hiking trail that connects SCRR to HWY 1, JUST south of the southern landslide road block. ~6 miles
#1 and #2 were great, well maintained fire roads. The climb up to the ridge was steep, probably a bit steeper than Naciemento-Fergusson, but there was virtually no traffic, so it was really enjoyable. I don't recommend part #3 (we did it so you don't have to!), but once you're on the ridge, you can connect up to the top of N-F Rd. Basically, you could ride all of (open) Big Sur, then get back to the detour while avoiding retracing your steps to N-F.
I posted a journal entry about this in great detail with photos here:
https://www.crazyguyonabike.com/doc/page/?o=1mr&page_id=525959&v=1J#pic_3175093Hope this helps!