I think the length of the rope would limit the extension to around Fillmore. Remember the Cal Cable carhouse and winding machinery were located at Hyde & California so the second rope all the way to Presidio was feasible. As it stands now the conduit, channel or gallery carrying the cable up to California would need to be upgraded for 2 ropes. Up to Clay it presumably is adequate for 4 strands but the rest I dunno.

This would be a good opportunity to do repairs on the existing California trackage and maybe introduce some improved tech, if such were available. I do not favor the "purist" museum approach but favor adding every tech improvement that comes up and that upgrades safety, operations and keeps costs under control.

The idea of a corporate go-fund-me is excellent and if interest popped up that might get stodgy officialdom motivated. What's changed now is DPW is not around to oppose rail operations as it did in the fifties.

Another possibiity is to roll in the estension of the Mason St. cable to the Wharf proper. That project actually made into official plans and grant applications IIRC but never was actualized. Like the electrification of the #71 bus.