Need ~17 days ~7,500 mile for route 1 or ~5000 miles for route 2.
Route1: Houston -- Rocky Mountain -- Yellow Stone -- Lolo National
Forest -- Seattle -- West California -- AZ -- NM -- TX
See the following map for an intuitive image. http://maps.google.com/maps/ms?
ie=UTF&msa=0&msid=111636382919445332818.000484ecdf8f55451c509
Route 2:
Houston -- Rocky Mountain -- Yellow Stone -- Salt Lake -- Arches -- Zion