Hey there @PhotoAdventurer! We went on a backpacking trip to Grouse Lake in the Mokelumne Wilderness just south of Tahoe last weekend (off of Blue Lakes Rd). The trip to Grouse can be done in a day hike (12 miles round trip), but there are a few smaller lakes on the way and a few short summits you could do as day objectives. We only ran into two other groups the whole time (so not super crowded by Tahoe standards). The most impressive part was you are above treeline for a good portion of the hike, so you get expansive views down towards Yosemite and over to the crest. It's going to be on our favorite hikes list for sure!
Desolation Wilderness in general. It is the most visited Wilderness area due to easy access but it is amazingly beautiful and if you pick your time you may find yourself alone or very nearly so. Particular hikes I have done are Mt Tallac from Spring Creek, Eagle Falls to the Velma Lakes area. Echo Lakes to Aloha lake. Most of my trips have been in October when it is cooler, but if you plan go then pay particular attention to the weather since it can snow and get cold fast and then warm up and thaw causing spring like conditions in the creeks. It is a Wilderness Area so your safety is your responsibility.
Another beautiful and popular trail is the Rubicon trail which goes along Emerald Bay. Again pick your time. Its probably fairly crowded on a nice Summer weekend but had much less traffic on a nice October weekday..when I did it.