I am going to assume you mean KTVL, two days, one night, and want more nature than tourism. Shoulder season at the lake, but that is to your advantage.
Arrange the rental car at the airport, arrive in the morning. Stop somewhere and get at least a twelve pack (or the eco-friendly equivalent) of water bottles. Drink one every two hours. Drive up to Emerald Bay. Park and do the Eagle Falls hike. If you want to hike more, go to Eagle Lake (bring two water bottles per person with you). Google for details, or use my preferred hiking app:
Hiking Project from REI. As previously mentioned, snow can be an issue, still, so I would suggest boots vice athletic shoes for hiking next week, just to be safe and comfortable.
Ready to eat after that for sure. Go to the
Red Hut. Great for breakfast and lunch, decent brews available as well. Or, if you are just a brew type for lunch,
South Lake Brewing Company. Go check in to your accommodations. Nap (I would!).
Wander around Heavenly Village if you want the tourist deal. Lots of kitschy but interesting shops.
If you want an early dinner, hit the
Chart House for happy hour. Great views, but get there right at 4 to get a seat in the room with the views.
Best fine dining IMHO is
Edgewood, also excellent views, make a reservation now.
Several good dinner spots in Heavenly Village at a lesser price point, we tend towards
Base Camp Pizza,
Azul, and
Kalani's, depending on our mood.
Harvey's used to be my favorite casino, if that is something you like, but nowadays they are all so intermixed it gets hard to tell them apart. Probably be less than vibrant wherever you go, sholder season and all.
Use the rental car to go driving around some more of the lake, just be mindful there is a lot of construction these days.
NV 511 for info.
Hope that helps or at least gives you plans to deviate from, PM or Email if you have any more questions. I hope to be up there myself next week, tearing a fireplace out of our place and installing a gas stove.