There's a shuttle from Devil's Postpile to Minaret Summit in Summer. I just looked--they end Sept. 5:
http://www.nps.gov/depo/planyourvisit/r ... mation.htmAfter that, private cars are allowed on the Minaret Road without restriction. Hitchhike or hire a cab from Mammoth Lakes. The first method takes forever, but is free or cheap. The second method (cab) is faster, but more expensive. You could take the cab to Mammoth Lakes or to Lee Vining junction (with the Tioga Road). Hitch hike up Tioga Road--also time consuming. It's better if one of the "we" is female--less intimidating
. Or take the bus to Carson City, then on another on to Merced.
Or drop off a car at the other end--certainly faster than taking a several legs of bus trips or hitch hike runs.
It's better to do this in the summer (or at least before YARTS and the Minaret shuttles shut down). Then you an take the Minaret shuttle bus and the YARTS shuttle. That's the best option from my point of view.