Scenic route from Santa Fe to Farmington, NM

US 550 does go by (25 miles or so) Chaco Canyon Nat'l whatever and it is 4 lane the entire way from Bernalillo to Bloomfield near Farmington.

Thank you guys; US84/285/64 it is then.

The first option is the most scenic. US550 would be the fastest and easiest.

If you want to split the two, a third option is US 285/84 to NM 96 to US 550. NM 96 is much more of a back road, a bit narrow, and you have to watch out for cows, but we have taken it and it was fine. But, for us it is shorter than going down to Santa Fe and US 550.

David

Your first option, 84/285/64 would be more scenic. US 550 would probably be faster as it skirts by the mountains. Even though 84/285/64 goes through the mountains, there was nothing that created any difficulty.
We took 84/64 last summer from Santa Fe on our way to Durango and enjoyed the drive. Our last trip over 550 was a few years ago when much of it was under construction. There really wasn't much to see along that road.