Crag access by Public transport is pretty grim, and remember how big the national parks are.
There is one bus a day Yosemite-Touloume Meadows-Mammoth Lakes (i walked the last 4 days of the John Muir) and the Meadows and Yosemite Valley both have free (but unlinked) park buses. Half-dome by the chains needs a pass, half are reserved for thru hikers.
The www says there is a bus four times a week Yosemite to vegas (via Death Valley)
Joshua Tree park, Smiths Rocks, Needles none to my knowledge.
I agree with City of Rocks+Castle Rocks Idaho as a possible destination but that is a long way even from Smiths Rocks.
Post edited at 17:55