If you are taking Tioga Pass and 395 to get to SLT, I'd recommend you pick up CA-89 at Topaz. This will take you over Monitor Pass and Luther Pass and is a lot more scenic than the NV section of 395.

Why would you be going to Truckee? If you are heading for SF after Tahoe, I'd take US-50 to Sacramento to pick up I-80. However, time permitting I'd plan on driving all the way around the lake as a "day trip" while you are there - it only takes a few hours driving at a leisurely pace.