I'd suggest 120 as the better route, as my memory serves (danger Will Robinson!) the roads through Benton Crossing are MOSTLY not paved. And you would only miss a few miles of 395 by taking the more direct route to Lee Vining.
I'd also highly recommend 207 into the Tahoe Basin. It's a much nicer ride than HWY 50. If you can spare the time a really excellent detour route is to take CA 89 west from 395 just south of Topaz lake and the Nevada border, go through Markleeville to Woodfords, and hang a right on CA88. This takes you into Nevada, and just a couple miles south of Minden (my prior residence for 15 years) you find the junction of 207. FYI, that route CA88 is ranked number ONE in N. Calif. motorcycle roads in the Destination Highways book.
At Tahoe, 207 intersects US 50 just a bit north of the Casino area at the south end of the lake. Turning north you can either follow 50 back to Carson City, or take NV28 to Incline Village, then 431 over the top of Mt Rose summit and back to 395 just south of Reno. As someone else recommended, a trip through Virginia City can be fun, to do this I'd just go down through Carson and take US 50 west. The road from Carson to VC isn't that much fun, but if you take the alternate "Truck Route" near Silver City there will be a little less traffic. After leaving VC headed towards Reno, the road called Geiger Grade is a bit nicer piece of pavement, with a couple of nice overlooks as you drop down the hill towards the Truckee Meadows and Reno.
Can't recommend highly enough CA89/88 thru Markleeville, not a lot of traffic, and some nice bendy road too. If you're looking for a different sort of dining experience, try one of the Basque style family dinner places in Gardnerville (The J-T, or the Overland). And if you go to one of these places, and like a interesting sort of pre-dinner cocktail, ask for a Picon Punch...you may be pleasantly surprised. If you don't stop in Gardnerville, but perhaps spend a night in Reno, try Louie's Basque Corner on 4th Street a couple of blocks east of Virginia St. (the main drag). (MMMmmm, my mouth is watering just thinkin' about it! LOL)
One other thing I'd mention, traveling across that Cedar City/Tonopah/Lee Vining stretch....don't pass up too many gas stations...they are few and FAR between!
You're gonna have a great time!
(Feel free to PM if you'd like more feedback)