7) The Sierra is a big place and it is hard to recommend something without knowing about your experience level and how long you want to be out for. The JMT is a good place to start. The High Sierra Trail (not the Sierra High Route) is another. I like Kings Canyon and Sequoia more than Yosemite. If you want to see some pics, take a look at
http://cwillett.imathas.com/shr/index.html
There are lakes everywhere in the Sierra and finding one to camp by is pretty easy, especially if you're willing to get off a trail for a few hundred yards.