Nobody can give you an answer to that because there are simply too many variables in your problemA route that you can legally and safely walk down is very different than a route that you can legally and safely drive down so you immediately have to toss out any answers that people got from mapquest et al.My best guess would be that you can probably double the distance that you would get from mapquest et al
3327 Miles. It would take you 48 hours of driving to do it. I have no idea how long it would take to walk it. A lot of this is covered by route 40
Based on 3327 miles. as said before. The average walking speed of 5 mph. would be about 665 hrs. approximate days would be 27- 28 days.