Weather cools down this weekend with a chance of precip, maybe thunderstorms, nothing bad but be advised. Staying in Truckee with limited time, you'll probably want to visit the region from the NE to SW corners of the lake along the west side. The east side is very dry and isolated with lots of mountain bikers on the trail near the access points. The famous Flume trail in the Northeast corner of the lake is awesome, but somewhat advanced. If you can rent a bike, just about any section of the Tahoe Rim Trail (TRT) on the north west area is great biking. I really like it around Martis Pk. and the Paige Meadows areas. Many other options nearby Truckee also.
As alluded to by others, many Tahoe hikes are famous for wildflowers, but the season for that is passed. These areas are mostly in the south shore and are due to the rich volcanic soils that have not fully eroded. Mt Tallac is an example and it's located in the south western corner of the lake, a long but scenic drive from Truckee. It's set back so you don't get lake views until nearly the top. Great hike to consider for a full day adventure. Climb is about 3,500ft from most trailheads. Lots of online info.
On the western side is Desolation Wilderness, which is mostly exposed granite similar in terrain to the High Sierra, but in the 7,000 - 10,000 ft range. Lots of lakes and great views from peaks and passes. I recommend entering Desolation via the Bayview trail at the back of the Bayview campground above Emerald Bay or the Eagle Lake/Eagle Falls trailhead right off the highway above Emerald Bay. These trailheads are nearby each other and make a good semi-loop. The Bayview climb presents great views that just keep getting better. You'll pass Granite Lake and then merge with the trail coming up from Eagle Lake. You could also come up Eagle Lake. At this point you have many options. I recommend a cross country route mostly south up Maggies Peak for lake views that are better than Tallac because you are much closer to the lake. No real trail, but just keep climbing south. There is another Maggie's Pk nearby and they're both good, but if you do the western peak you're in a better position to keep going. After Maggie' Pk, you can head further back to Dick's lake and Fontanelle Lake, both gorgeous cirque lakes. If you've still got gas in the tank, go for Dick's Pass - another +1,000 ft to incredible views down into the Aloha Lake basin to the south. If you still have energy, go for Dick's Peak. That would be extreme but doable. On the way back you could drop down to Eagle Lake and then loop back up to your car. You might prefer to go up the Eagle Lake trail then back down the Bayview - this would be easier on the knees in that direction - lots of granite steps above Eagle Lake.
Mt Rose is the tallest peak on the north shore. Great hike, waterfall might be dry or low but the peak views are spectacular in all directions. That's around 9 miles RT from the TRT trailhead at the road summit. The drive over Brockway summit is much faster than going through Tahoe City.
Another fantastic hike is a popular trail along the lake from DL Bliss State Park to Emerald Bay. It's a easy/moderate more gradual up and down along and above the shoreline. This might be a good warm up hike before you tackle a bigger adventure. There are some great cliff jumping spots starting about a 1/2 mile in - look for other people or ask around if you're interested. That hike takes you to the back of Emerald Bay to Vikingsholm Castle. Lots of other options around Tahoe, but I rate these all very highly. No chance of disappointment.
Have a great time and enjoy the best of Tahoe!
