I'll be driving from San Francisco to New York this summer. I'm budgeting 7 days for the trip and would like to get a flavor of middle America but without being delayed too much. Many books have been written on US-50, but I'm worried that US-50 would be too slow to be able to drive coast/coast in a week (I know the part of US-50 from Sacramento to South Lake Tahoe--it's a two-lane road that's not nearly as fast as US80. One winter we drove on it to get to Tahoe and the trip took almost 12 hours from the Bay Area!)

Can anyone tell me what I should expect my average speed to be on US-50? Alternatively, does it make sense to drive on this highway only part of the way (perhaps western US) and then switch to a faster highway? Since US-50 doesn't go through many large cities, will I be able to avoid the rush hour traffic that's more common on highways such as US-80 and compensate for the lower average speed limit?

Thanks a lot!