Not sure where you are staying, or if you will have a car.
If by chance you're in south lake, and you have a car, you could take one day to drive around the lake at a leisurely pace.
Do it clockwise (see google earth)...... Then you'll hit Emerald Bay in the morning....there are some nice, easy short hikes there, and before there at camp Richardson.
Drive on through some of the smaller ski resorts on the west shore, then on to the north shore for some lunch.
Then down the east side there's lots of places to pull over and scramble down to the lake for an afternoon swim.
Then back to the south shore for dinner somewhere, maybe a couple hands of black jack.
Relaxing drive with short lunch/brunch break only is 4 or so hours.
Could be an all day event with a hike and a swim and dinner thrown in.
Lots of photo ops on the drive.