The PCT roughly runs from Yosemite to Lake Tahoe, right?

Yes, the PCT does run from Yosemite to Tahoe. So does the Tahoe to Yosemite Trail, which if I'm not wrong, is a better route.

From South Lake Tahoe, you could bus it to Carson City, then bus down to Lee Vinning, then shuttle (or is it hitch?) to Tuolumne and shuttle to the valley.

A map:
http://postholer.com/gmap/gmap.php

The TYT and PCT segments are both around 180 miles.

I am not sure if I understand your question,but the PCT runs from the boarder of Mexico to 10 miles into Canada.Sorry if that wasn't your question.

All of that hiking would be about 570-580 miles.

Make it easier. Skip Toulemne Meadows down to Happy Isles. Do the TRT, head south on PCT and then do Whitney and head out Whitney portel. Theres a bus that runs up the east side (google crest & bus) all the way to reno. You miss out on about 25 miles of IMHO less than spectacular hiking. The only highlight is Vernal and Nevada falls but you can do that as a tourist from Yosemite valley. This will make logistics much easier.

If you must do all the JMT then take the hikers shuttle from TM down to the valley. It leaves sometime around noon. The problem will be that technical you will need seperate permits since you left the trail. You could sneak your way back up to TM and pretend you never left the PCT. Your call.

Dan, when are you looking at doing the TRT and heading to Happy Isles? I live in Reno and will be heading to Curry Village to start my JMT hike in August. Getting from South Lake Tahoe to Reno is a piece of cake. I can give you a lift if it times out right. The only downside, is we have to shuttle a vehicle to Whitney Portal before we head back to Curry Village.

This thread inspired me to buy the guidebook. It was last published in 1987. Glad I bought it before it's completely gone. I bet I'll to the TYT someday..