Just passed by your area about an hour ago heading to Easley to visit the in-law and meet up with other family over the holidays. I could give you an hour or two full if you want to meet up and you have an Atlas handing. We homeschooled our two also and made it wonderful giving us the opportunity to make two long trips.
Make sure you check out the Junior Ranger program. Special activities for the kids and the badge for completing it. Will make the kids learn more about the park then they could by just walking around. My girls would sow them on a vest. They eventually had so many we had to add material to handle more. It was something to see Rangers wanting to have their picture taken with the girls.
When you get to Grants, NM there is a KOA right on the interstate which makes a nice late pull in. In the morning, don't get on the interstate but head to El Malpais and spend an hour or two. Then head over to El Morro. You can either spend the rest of the day and spend the night in the campground, or just a couple of hours. Finally swing by the Petrified Forest and drive all the way through the park before getting back on the interstate. There are some areas in the park that will remind someone of the Badlands if they have been there. Even if you don't do El Morro and El Malpais, make sure to do Petriefied forest as it will only add an hour or two versus stuck on the interstate.
