My wife and I are planning to drive from the Baltimore area to Yellowstone in either January or February. We're familiar with the East West Interstates (40, 70, 80, 90 and 94) during summer but not in winter. I've been reading posts about I-90 but they all seem to be 5 or 6 years old and deal with travelers from the west, especially thru Idaho and Montana. Is I- 90 the best route to take from Chicago thru Indiana, Iowa, South Dakota, Wyoming and Montana? Or should we stay south to Denver? We're planning on taking 10 to 14 days to do this so we can hole up if weather does get bad.