Bus links; scroll down for the hiker's bus and YARTS:
http://www.nps.gov/yose/planyourvisit/bus.htmBoth buses have limited schedules but can work OK with a little planning. From our experience, leaving a car in Tuolumne and catching YARTS back up from the Valley after the trip was preferable, but your circumstances may certainly vary. The Valley's a zoo in mid-summer, particularly around the weekend. Pleasant alternative is to catch YARTS at the end of the day after pizza and beer in the Valley, be chauffeured back to Tuolumne, and grab a campsite in the backpacker's campground before hitting the road the next day. We were leaving the park by Tioga, so this worked very well. If you were headed west, it adds road time and mileage. The buses make stops at Crane Flat and White Wolf which might give you more car drop options.