Until 1954 the Cal cable went from California & Market straight out California St. to Presidio Ave. California St. cable cars survived the elimination of half the system in that year but were truncated to Van Ness Ave. My understanding is the the Fairmount Hotel and the Swigs were instrumental in saving that part of the line.

Over the years it has been mooted to extend the downtown end to the Ferry Bldg. proper but the argument is you don't gain much but some operational issues with Market St. traffic.

When the California line was built its initial terminus was Fillmore. It appears that the parallel Sacramento & Clay Sts. line also ended at Fillmore after 1906. So there is the historical precedent. Washington & Mason winding machinery have room on the sheaves for another cable, which would be needed for the extra 8 or so blocks to Fillmore.

The 1954 arrangement with the stub at Van Ness has been noted by many and some in SF officialdom as half-assed, with some ideas that have been proffered but the Fillmore extension is the best. It may not be possible to have stops at all the intersections due to the traffic craziness. Stopping in the middle of Franklin may not be safe enough in the real world so you may have to skip that one. It would be a shot in the arm for the Fillmore merchants and there are victorians to see enroute and a connection to the #1 California trolley bus at Steiner.