There are many options that are not the JMT and easier to arrange. You can get permits online or half the permits are held for same day release at the ranger stations. We often go the station in an area we are interested in, get a permit that is available and go exploring for a few days. These have been great trips. JMT is actually quite a busy route in the Sierra. Others are much less travelled. One of our favorites has been South Lake to North Lake out of Bishop. We also really enjoyed exploring Shadow Lake, Ediza Lake, Garnett Lake, etc out of Mammoth. This year we are doing the high country (lake Italy, etc) out of Pine Creek trail head. We don't have any set plans, just will go exploring for 6 days. I hope you get out there. The eastern Sierra is spectacular and considered among the best backpacking in the world.