Bob said "The morale is, don't count on any quick hitchhiking." Boy, do I ever know that! Last summer I did the loop solo. I came out at North Lake Saturday morning about 10:30 am and was able to hitch a ride to Highway 168. I figured it would be no problem to hitch a ride to the turn off to South Lake. I ended up walking all the way past the little town of Aspendell (probably 3 miles) and finally got a ride to the turn off. I then had a number of cars pass by as they turned on to the little road. Finally, I just stepped in front of a truck and as they were telling me why I couldn't get a ride I jumped into the back of the truck!
Coming off a trail and then having to hike down an asphalt highway in the sun is not my idea of fun! I could not believe how people just cruised on by. Sometimes, I stood way out in the lane to get their attention, but, they just drove right on by. It looks a lot easier when you are looking at it on a map.
I've done this trip 2 times. Once solo, another with all of my kids and some friends. Solo, I started at 6:30 pm the first day, Wednesday, from South Lake, stayed at Long Lake with hard rain from 3:00 to 6:00 am. Rain stopped and I headed out about 7:00. Beautiful day until about 3:00 when it started raining and hailing at Big Pete Meadow. When I got to Little Pete I decided not to go over Muir and was glad I did. The next morning it was clear and I got up early and hiked over the pass and made it to Muir Trail Ranch (a bit off the North Lake / South Lake Loop) to sit in Blaney Meadows. The next morning I hiked up and over Paiute. Spent the night at the lake closest to the pass. Out Saturday am.
With my family, we left the South Lake trailhead at 2:00 pm and camped on the other side of Bishop Pass as my daughter in law had an IT band inflammation which made she and my son turn back the next morning. The next day the 6 of us hiked down Dusy, to Le Conte, over Muir and camped at Evolution Lake. The next day we hiked from Evolution lake down the canyon and then up Paiute about 3/4 of the way. We were out Saturday at about 11:00 am. So, it can be done in 3-4 days and days would be great.
Also, I have hiked it both times from South Lake. I think doing it from North Lake would be nicer for 2 reasons: 1. Once over Paiute the trail is pretty easy down to the bottom of the canyon. 2. I think it is a better way to see Evolution Valley. When we hiked the JMT a few years ago we stayed at Colby Meadows in Evolution Valley. It's quite beautiful.
We packed a mule train and told them our route and they said, "so, you're doing it the hard way".
Let me know if you have any other questions. It's a beautiful hike and you get to see some of the most memorable parts of the JMT.