I wouldn't want to ride on U.S. 50 in CA. Actually, you can't ride it until a bit past Sacramento, but the freeway portions would be the least of your worries. Lots of Yo-Yo drivers, limited or no shoulder with some tight curves and descent inclines would be a recipe for road pizza with you as the topping.

If you were looking into U.S. 50 because of its length, maybe you should try U.S. 20 (starts in OR). http://en.wikipedia.org/wiki/U.S._Route_20 Except for the gap in Yellowstone, it apparently goes coast-to-coast, although there appear to be a few freeway issues on it too.