We went to Lake Tahoe for our honeymoon this summer. It's absolutely stunning there. Check the average weather, because honestly, it may be worth it to fly into San Francisco or Sacramento just for the spectacular drive up to Tahoe from there, but if there's likely to still be snow in the mountains, then it's less worth it. I can't imagine dealing with tire chains and a rental car. We flew into SFO, and spent about 24 hours in the city before we drove to Tahoe. We went to the Walt Disney Family Museum when we were in SF, as well as Muir Woods, and both were well worth a visit. We stayed in South Lake Tahoe, so for us it was about 3 1/2 hours drive time. Not too bad, and a very easy drive most of the way. The drive over the mountains certainly isn't "easy", but it is spectacular. Coming home we flew out of Sacramento, because to get back to the east coast on a Sunday from Reno our only options were overnight flights or flights with more than one stop. Well worth the quick drive to Sacramento. Heading back to SMF, we stopped at the Marshall Gold Discovery State Park, which is where gold was first discovered in CA. Again, well worth the stop.
IF they are running it for sight seeing in May, you MUST take the gondola to the top of Heavenly Mountain. The views are worth EVERY penny. It's on the south side of the lake, but the drive around the lake is also worth it. Also, make sure you drive down to Vista Point, overlooking Emerald Bay. Just stunning. We found Truckee to be a neat little town too. We spent a bit of time shopping and had lunch there.