Don't know how I've missed this. Lots of good advice, I'll chime in as well, taking the comments in order, to start:
First, I'd discourage a trip to Northern New Mexico and Southern New Mexico in the same vacation. It can be done, but I think it'd be a beatdown. For example, it's nearly 400 miles from Chama to Carlsbad, and a lot of it is through areas that aren't very scenic. And once you're done in Carlsbad, you're over 600 miles from home.
Your mileage may vary, pun intended. Total up the travel time, allow for your tolerance for travel, and make a decision.
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Meow Wolf, never been, but everyone recommends it.
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Albuquerque Sandia Peak: I can go for either the drive or the tram. Check prices, it's about $112 plus tax for your family to do the tram. Fun ride, some great views. But you can go to Tijeras, and drive up the back side for the cost of gas. You get the same views from the top. We've eaten at the restaurant up top, didn't get a good table, and the prices reflected the view which we didn't get.
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Train at Chama. I think your kids are barely old enough to enjoy it. Kind of depends on their interests. The engines are cool, the scenery is gorgeous. We rode the train one way, took the bus back. I think that's the best, and still makes for a long day.
If you search the web site, there are shorter trips out of Chama, such as riding midway and back, rather than going all the way to Antonito.
I love the Cumbres and Toltec train, but I'm a train nut. It really is a bucket list item for anyone. I like leaving from Antonito, because the train yard there is full of cool old equipment. If your kids enjoy mountain scenery and old machinery, I'd do at least a short trip. We have bought tickets for inside the cars, but we spent the whole trip riding in the open gondolas.
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I'm a huge fan of the TEXAS! musical in Palo Duro Canyon. Again, I think your kids are just old enough to begin to appreciate it. Budget two days, because you'll want to hike the canyon, you MUST visit the Panhandle-Plains Historical Museum in Canyon, and the play ends late, so you'll be spending the night in Canyon or Amarillo.
Is it too much on top of a trip to Chama? Yeah, maybe.
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I'm a bit confused with the poster who says "Angel Fire is a must" (northern New Mexico), and then links to White Sands(southern New Mexico). Angel Fire and Red River have been playgrounds for Texans in the Panhandle for decades. Red River is one of the best family fun spots in northern NM, but would add a lot of time to a trip to Santa Fe and ABQ.
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Now to my recommendations in order of travel. Some of these I'll just mention, you can Google them, or ask me for more details.
Copper Breaks, Caprock Canyons, and Palo Duro Canyon are all wonderful state parks approximately on your route. The Charles Goodnight home, Goodnight, Texas, is a nice stop for fans of Lonesome Dove and Panhandle history.
Again, highly recommend the museum in Canyon. Please don't waste time going to Cadillac Ranch in Amarillo. But there are several little Route 66 alignments off of I-40 from Amarillo To New Mexico if you are into that.
In New Mexico, Russell's Truck Stop just past Glenrio has a cool free car museum. Tucumcari has the most unchanged Route 66 alignment you'll find, and Del's Restaurant is still a good place to eat. Blue Hole at Santa Rosa is fascinating, and the old car museum isn't bad. Also has some Route 66 sights.
I assume you would leave I-40 at Clines Corners, a tourist trap since 1939. Going up 285 toward Santa Fe, you pass Lamy, which still has the train station from Manhattan Project days.
My don't miss in Santa Fe is Clafloutis for breakfast, r at least croissants
The drive from Santa Fe to Chama has some pretty spots. Los Alamos has great Manhattan Project history and museums, and some fantastic views. Bandelier Monument is cool, and Valles Caldera is one of the prettiest and most amazing places in New Mexico. There's a lot more to say about Los Alamos, but I won't bother unless you want more info.
Abiquiu is the former home of artist Georgia O'Keefe, after we ran her out of Canyon. A mosque owns land near there called Plaza Blanca, and allows you to hike. It is an amazing place, worth the diversion.
Again, Chama is pretty, the train is fun, worth the trip in my opinion.
Returning to ABQ, you can take 550 through Cuba. More deserts, more desolate, but it does have some amazing desert views. Maybe nt so great for young kids.
In ABQ, the Biopark (zoo, aquarium, gardens) is worth a visit. I think the kids would enjoy the natural history museum. The National Nuclear Museum is great, but may be above them. However, they have lots of cool planes on static display out back, if they're into that.
If you do want to throw in Carlsbad, that's where the Desolate Drive comes in. Clines Corners to Vaughn to Roswell. Ugh. And don't bother with the UFO crap at Roswell.
You could go ABQ to San Antonio, NM (have a green chile cheeseburger at the Owl Bar) and drive across north of the Trinity Site to Carizozo. Further on, you can go to Lincoln for Billy the Kid stuff.
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Well, that should be a crapton to start with. Reply or PM for more info or explanation.