Originally Posted by
Doug64
I'd recommend the ACA's Trans AM or the Northern Tier routes.
My wife and I rode from Newport, OR to Boston, MA in 2007, roughly following U.S. Highway 20. It was a great ride. Highway 20 is the longest contiguous coast to coast highway in the country. We have done several long tours before and after this ride, but riding across my own country was pretty special....
Here's confirmation of that statement:

We live within about a mile of that eastern terminus, on Rte 20 (Commonweath Ave).