Federal law says as long as the firearm is legal where you live and legal at your destination, you are protected while transporting it. If you are transporting it in an airline approved case (in other words, it's locked), and it stays locked in the case until you get to Nevada, you will be ok. You are not "importing" into CA.
You did not say if you are flying from Sac to Tahoe or driving, or if the place you're staying at Tahoe is in Nevada or CA. If you're flying then there is absolutely no problem as your luggage would be checked through. If you are driving just make sure you don't make any side trips while in CA. If you are staying someplace on the CA side of the lake then you are SOL.
As another thought, you could have the gun shipped to you at the hotel you will be staying at.
Yet another thought. If you are driving to Tahoe I assume you will be renting a car. If that's the case it will have CA plates. When you go back to Sac and drive through the Ag inspection station use the lane that says returning locals, and even if they are stopping everyone just say you don't have anything (fruits, plants, whatever).
Better yet if you are driving to the lake, take Highway 50. We are very cool up here and more than likely any CHP or Sheriff you encounter has more ARs than you do. Plus the Ag stop on 50 never stops the local returnees.
And if you are REALLY desparate, just stop by my place off 50 and I'll let you take one of mine over to play with.