We had a passing thought about doing that this Summer. We basically followed the Lewis and Clark route from about Ashland, Kentucky to Butte, Montana. Following the Ohio then the Missouri Rivers to the source of the Missouri. That had already put us at 3+ weeks on the road, over 7 thousand miles round trip. The time to get us to the Pacific and back to Virginia was a bit too daunting time wise and $$$.
We're talking about possibly flying out to say Seattle, or Portland sometime in the future and hit some spots we missed. I really want to visit Idaho and the Canadian NW sometime.