What about using Uber in a nearby town? I bet there is Uber in Fresno. There is good bus service in the San Francisco bay area. One bus stops at Point Reyes. There are also commercial shuttle services on the east side of the Sierra. Also a shuttle service out of Pinedale Wyoming. Not cheap though, at least $100 to be taken to a trailhead. I still occasionally hitch hike between Sierra trailheads. So, far pretty good luck.

Going solo is expensive. If two people drive in one car that's half the cost and pollution. Also, since entry fees to National Parks are per car, only one entry fee. I used to meet people in towns near Yosemite and then we would go in with one car. Many of the costs associated with backpacking are "group" based. The solo backpacker gets hit hard with fees. Always kind of irks e when I go into King Canyon that I pay the same backcountry fee for my permit as a group of 15 even though I do 1/15th the trail damage and other impacts.

Yeh! for Yosemite with its per person fees for the backpacker campgrounds and Camp4 in Yosemite Valley.