"With the advent of the E-bike, a ride to the top of Cone Peak will become commonplace some day."

I sure hope not!

The Dolan Fire was helpful in removing some brush from the trail system. The Slo Mtn Biker community may be interested in creating a downhill ride along the length of the old Mill Creek trail (some trail improvement may be needed after the recent mud flow down Mill Creek). That ride would make for a much easier car-shuttle than the Prewitt Ridge ride.
With the advent of the E-bike, a ride to the top of Cone Peak will become commonplace some day. The ride from Cone Peak Road will be exhilerating (maybe this should be disallowed?)
Another fascinating possibility is a ride to somehow get to the top of the Willett trail then ride that down to highway 1.

Mountain Biking the Ventana is a silly discussion. Most of the trails are 100% not bike friendly: too steep, too loose, to slanted, too rocky, too silly. I am an avid Mountain biker and hiker/backpacker and anyone that has done both understands the engineering and flow of a mnt bike vs a hiking trail is wildly different. You can never successfully convert Ventana trails to be bike friendly. Period.

on the hand I have often day dreamed of riding my gravel (not mountain) bike on some of better dirt roads. That would be awesome !

Some friends walked the Prewitt loop recently, they said there were many trees down, they had difficulty following the trail, and the tilt of the trailbed was problematic over time. They crossed some poison oak which was in the trail. There was a precarious crossing of an old mud slide near Stag. All these issues seem to combine to make a bike route through the Prewitt loop unlikely.
The good news is that there is apparently a bike route from San Martin Top to highway 1 (according to trailforks).

Well, that's not necessarily a bad thing (if the mountain bikes are ridden by responsible people, that is); it could bring more people to the region, and thus make the local tourism industry more rentable.

Personally, I rather enjoy the Prewitt trails from either north or south entry points on a bike. Sure, there is a lot of hiking and pushing the bike, but the raw terrain adds to the challenge and uncertainty as to how many miles you will travel on any given day.
It is rather unlikely that the full loop will ever sustain any significant trail work without more traffic and regular maintenance.
I feel the same about pushing to the top of timber top, quite a challenge but what a beautiful payoff for all your hard work. ;)
I love that both of these trails are available for bikes.
Frankly, most mountain bikers do not want anything to do with either trail due to the physical torture necessary to properly enjoy them.

This is a fantastic idea !

Some slight modifications will need to be made to the trail.
The switchback corners along the southern section are too tight for bikes, maybe that can be resolved with some SLO mountain biking muscle, a digging bar and some shovels. The tightness of the northern section of the trail can be bypassed by using the existing mountain bike route. The middle section is a little brushy but maybe that can be resolved by a posse of lopper weilding riders.

It interesting how folks want a downhill ride. However there is a trail that is a 13 mile loop in Pacific Valley. It has redwoods. streams. great views and much more. It also connects to the downhill ride from Plaskett Ridge. The trail name is the Prewitt Loop Trail. South end starts near the Ranger Station, the north end is about a 1/4 mile north. It would be a lot of work but a great reward to hikers and cyclists if it was ever completed. The CCCMB about 10 years ago cleared the North Side to the Slide Past Stag Camp but no one ever finished the job. The first mile on the north side is relatively clear. When we hike it we usually go to Stag Camp, the ascend the ridge on our way back for some great views.

Splain is right about the north coast ridge rd, that is a long walk up. Only the privileged few have the rights to drive up there.
Maybe the best idea to harness the energy of the mountain bikers is to offer the Boronda trail as the reward for assisting in some trail clearing action. The VWA insiders can fetch trail-clearing bike riders at the bottom of the the north coast road, they are asked to do a days worth of trail clearing before they are dropped off with their bikes at the top of the boronda trail ! (bomb's away!)
Another idea. Whenever someone speaks of bicycles on the vwa site, immediately delete that and put up a note "no speaking of mountain bikes is allowed on this site.", or erase it and put up the note "mountain bikes are not allowed in the wildernes. Please go away". hahahaha

You may be mistaken. I found the below routes in the area. Note the fine video which can be viewed related to the Prewitt ridge ride.

https://www.trailforks.com/trails/prewitt-ridge-trail-dh-section/
https://www.trailforks.com/trails/plaskett-ridge-downhill/

The Mill Creek "trail" from near Nacimento summit down Mill creek would make an excellent ride if it were improved to make it more ridable (currently it seems to no ridable).

Another possibility would be to carve a trail from Alms Camp down to the Mill Creek trail (being careful to not trample on private property along the way).
The possibilities are endless... descend Plaskett Ridge Rd down to the gate, then follow the use-trail which leads to the 10 acre inholding and cabin at elevation 2300 ft (due west of the old fire lookout in the gated area of Plaskit Rd.), proceed down to the ridgeline north of the cabin to meet the Prewitt trail !
More madness? How about carving a route from San Martin Top, to above Treebones resort !
Insanity? Find what appears to be a use trail from Plaskett Rd towart the cabin at 2300ft, before reaching it, descend the gradual ridgeline which leads directly toward Plaskett campground (be careful to avoid private property near the campground )!

Be advised that these "possiblities" should be carefully considered and cleared with the appropriate authorities before being used. These lines on the map can be done without encroaching on private property or wilderness but care may need to be taken to avoid that.