Keep us posted about your trip, Charles! I'm thinking of doing a solo JMT next year (although there's a friend's daughter's wedding in Wyoming that may get in the way...) and I'm sure I'll face many of the same problems. I did it with my son three years ago, and it was a fantastic experience, but this time I want to go faster and lighter (and I ain't getting any younger...).
When I was doing logistics for the 2004 trip I ran across the same transportation problem at the end of the trip, but since I didn't have a car the solution was a no-brainer: CREST bus from Lone Pine to Ridgecrest, rent a one-way car (no extra charge) to LAX and fly home. The beginning of the trip was also easy because a guy came with us for the leg from Yosemite to Reds Meadow, so he could rent a car in Sacramento, leave it in the Valley, and return via YARTS from Mammoth.
Which reminds me: anybody on this board have experience with the train/bus service from Sac'to to Yosemite? Looks like I could fly into Sacramento in the morning and be in the Valley by late afternoon, but I'd sure like to talk with someone who'd done it. Reno looks like it would also work, but last I looked, flights into Sacramento were cheaper and the train/bus schedule was more favorable.
Snowy, where'd the $200 estimate come from? Was that for one of the commercial shuttle outfits that will take you anywhere anytime out there?