One of the best overnight backpacking trips I've done was to Desolation Wilderness. (See link below). I went with my boyfriend, who had never gone backpacking, and though he did have some heavy huffing and puffing to get up the mountain, it was perfect for beginning backpackers. We hiked up to Half Moon Lake, where we set up camp. We went on a Sunday, so there was no one else around, which was so spectacular...it really did feel like the place fit the name. The only problem with this hike is that it is snowed in most of the year, so you've got to call ahead about weather conditions. We had nice, warm hiking weather during the day, but it was pretty chilly (and windy) during the night.