Maryland to Washington State -- best routes

When time is not much of an issue try working in what used to be the main highways before the interstate system. Roads that carry names like the Lincoln Highway, The Pony Express Route, any designated scenic routes that can be included.

Interstates are great for what they are intended for, getting you there in a hurry, but they are virtually useless for actually seeing stuff like passing through old small towns, passing through farmland & seeing the 'history' of old farm equipment used as gate guards or simply left where they died.