HI Brett!
One of the main trail heads into the Sierras is Florence Lake in the Sierra National Forest. It is the starting point for hikes into Evolution Basin, and the northern area of Kings Canyon National Park. There is a boat shuttle service that bypasses the hike along Florence Lake. It generally runs twice a day, so if you miss the morning schedule, then you either wait until late afternoon or hike the lake. Another shuttle service is on Edison Lake that takes you to Mono Creek and the Mono Recesses. I remember rushing back one afternoon to catch the late ride across the lake. I am glad I had a watch that day. Both lakes are close to the John Muir Trail, and the shuttle boats are used a lot.
In regards to safety and redundancy I carry a satellite phone (12 oz). It saved my "cookies" about 3-1/2 years ago (You can read the details by searching the BPL Forums for "Satellite Phone Worked!") This light weight thing is very personal. I will try and limit the ounces wherever reasonable, but will always do what I am comfortable with (which keeps changing with time and experience). After fifty years of periodically hiking alone cross country into remote areas I now carry a satellite phone and do not hike alone – unless it is an area where someone is likely to come by within a day. I am sure that as time goes on I will become even more conservative, but if it means a few more years out on the trail it's worth it.
