As has been said on this site many times, a front wheel drive will work just fine for 90% of interstate travel. The reality is that 4 wheel drive is just not that much help when you are talking about travel at freeway speeds, and if anything people get overconfident, and forget that while 4wd provides extra traction to get your wheels moving, it does nothing when you are trying to stop!

Its also a big misconception that traveling south is a better bet. I-40 frequently sees winter ice storms in the planes and snow as it travels across several higher (7000 ft) passes through NM and AZ. Even I-10 can and does see winter storms, and in fact, has already been closed because of storms on a couple of occasions earlier this year. Quite frankly, northern crews are often better equipt to deal with bad weather and if there are storms that stretch from Wyoming to Texas, I'd personally most likely take I-80 to I-15. While this route is certainly not immune to stretches of bad weather, its avoids the heart of the Rockies in Colorado yet its crews will be best able to deal with poor conditions.

3 days for this trip is not impossible, but it really will be pushing your limits and will give you zero time for any extra sightseeing. It will become impossible if you don't see nearly perfect travel conditions.