Regarding access to Fountain, Edgar, and Mitchell Point... On July 19, 2020, I called Providence Mt’s State Recreation Area (760-928-2586) to get an update.
The peaks are not closed. A “backcountry permit” is required to access the peaks if you’re starting from the visitor center. You can only get this permit in person at the visitor center. (There’s currently a $10/vehicle entrance fee as well.)
There is a gate on the access road two miles down from the visitor center. It is only unlocked from 8 AM to 5 PM on the days they are open. So, you would have to enter at 8 AM, go to the visitor center and obtain your permit, then complete your hike by 5 PM. Otherwise, your vehicle would still be in their parking lot after closing time, and this would likely trigger a search-and-rescue operation.
Accessing the peaks via routes that don’t begin at the visitor center is a “gray area.” There is a route (DPS Route D) on Mitchell Point that begins from the Bonanza King Mine and does not cross any of the State Park land. That is fine. But other routes to Mitchell do cross their land. And the summits of Edgar and Fountain Peaks, and the established routes on those peaks, are within their boundaries.
I was told that “technically” you should have the permit to be anywhere in their backcountry. Even if you find a route up Fountain or Edgar from the west. But they are only really concerned with people who start from the visitor center.
The backcountry permits are available during these days of Covid-19. Their trails are open, while caves and the cavern tour are closed. But beware, the rules and situation could change by late summer or fall. So, it would be best to call and discuss what you plan to do before heading out there. They are currently open on Friday, Saturday, Sunday, and holiday Mondays.
The coordinates currently listed on this page place it at Edgar Peak. Coordinates should be 34.94613, -115.53751
Also, if I search the site for "Fountain Peak", this page doesn't come up, at least not for me.