I think that 60 in NM is an excellent choice. West of Socorro, keep an eye on fuel, because there are not a lot of stops between there and Springerville. The road is good, two-lane and smooth and passes by the VLA and VLBA sites (NRAO), also Pie Town - where you absolutely have to get some pie.
In Springerville, if you are into Mexican food, definitely go to Los Dos Molinos, it's on the south side of the highway coming into town. New Mexican style with Hatch chiles, it's a bit hotter. If you prefer BBQ, there is a great BBQ place on the west side of town as you are leaving town - Avery's. Apart from those two, there are a couple of other dining spots, but not as good.
180 is a good road too, lightly traveled and a good choice. It passes the southern entrance to the Petrified Forest and you can take Petrified Forest road through the park (for a fee), and see some really cool stuff - it too takes you to I-40.
I-40 through Northern AZ is like death rally 2000. The road can be rough in spots, so you may have to switch from right to left lanes to get the smooth, but everybody drives like it's their last day on Earth, even the truckers. Keep in mind this road goes through Navajo lands, and the Native Americans have a different philosophy about driving - be alert for them to do just about anything without a care of what is around them. Also watch for crosswinds across this area. If you make it to Flagstaff alive, you should celebrate. 🙂