We've been on almost all of US 50 from Placerville, CA to just north of Louisville, KY at one time or another. Most of it on our motorcycle.
In most places it is a good road, mostly 2 lane. The only stretch of it I didn't like was through Kansas City. You will have to travel I-70 from Grand Junction, CO. to the middle of Utah. The Nevada portion is known as the "loneliest highway" but we love it. There are 7 (if I recall correctly) passes over which you travel across the state. It is desolate but an enjoyable trip for us.
As we live about 40 miles north of it here in Missouri, we are on it frequently. It would make a relaxing trip but don't expect to make very good time. We figure to average 45-50 MPH while traveling on it due to traffic and towns.
Let us know how it works for you.