Don't know about 120, but 50 ain't no easy trip. But, I love 50, the loneliest road in America (that's what they say). Love Tonopah and even ugly Ely. Have a train museum there and a casino with a free RV park. There are a lot of steep passes on it as it runs east-west up and over the several mountain passes. The mountains run north-south formed as the glaciers melted and moved north. It's nice and flat between them. Couple of years ago we took a trip to Reno and since we had some time left, we thought we'd head east across Nevada to Utah and take in Arches and Canyonlands. Got out my mountain pass book (gives all of the grades of all mountain passes in the west). I think there were 7 or 8 passes with grades above 6% some over 8%. And parts of it have real tight corners. Since our "new" TV, a '94 GMC Suburban K1500 has a really weak, low compression engine (runs great, just no power), we decided it would be too much of a struggle for the sucky engine and instead headed north to home. (Made it to Arches the next year, coming from the north). We try to take the blue (two lane) highways all the time, go slower see more. If your rig has a decent engine you should be ok, but you rarely go over 55 on 50. Hard to make time on the two lanes.