I think you're being too conservative. I bet you can drive it in 4 days, with only 7 hours of "on-the-road" time each day. This assumes you are going to average 80-85mph on the interstate. If anything push it hard the first two days - 10 hours on the road, then take is easy for a day in Santa Fe, then finish up in a day and a half on days 4 & 5.