I've been to those parks a number of times they are all great. 1st buy this book by Laurent Martres called photographing the Southwest Vol. 1 Southern Utah heck get all three.You will have so many photo ops andgreat things to see so don't let the tail wag the dog Antelope and canyon x while great are cliche and literally hundreds of tourist are packed in there by lots of tour companys and you will pay roughly $500 for the 4 of you. There are so many slot canyons maybe not as pretty but safe and free and uncrowded and unhurried. Start at Cedar Breaks ( just above Bryce) it is the beginning of what is called the Grand Staircase (look it up). i take it you will be gone for a couple of weeks or more as it will take you that long to hit just those parks you listed. Arches is small and will be a zoo,Canyonland's island in the sky is great and will hold the attention of kids, as it is a 22 mile scenic drive with lots of different things to see, and the Needles section of canyonlands is on the way to MV so see it as well it is totally different big canyons cowboy camps that are 100 yrs old as well. I read last year they stopped folks from entering arches until others leave. Capital Reef is nice but about an hour away is a state park called gobblins your young kids will love it and it is a safe park they can run wild among the smallhoodoo er ah gobblins and it is fun see pic. Be sure to hit Kodachrome canyon another state park near Bryce lots of volcanic cores like this one. Buy that book! Oh when at Monument Valley do not attempt to drive the scenic road without a 4 wheel or all wheel drive it is not maintained and you do not want to get stuck. I've always driven it myself this way with no problem. if you take their tour you will be eating a lot of dust as it is open in the back with no cover so you will be hot and dusty during the 17 mile trip. also on the way to Monument Valley near Mexican Hat is the Valley of the Gods ( see michael Jacksons glove attached lol) it is free and a mini MV a 17 mile road windsthrrough geologic features like the glove. Also literally across the street is the Gooseneck of the San Juan you can do both in less then an hour. Zion is a vertical park emerald falls is doable for the kids but be sure to hike the Narrows if you can.Pink Sand Dunes is close by it just ok. Anyway have fun.

Some things to be aware of:

That area is so amazing that planning anything in a timeline is not going to survive the first stop. Photo ops are literally everywhere.

The crown situation depends on where you happen to be and varies greatly . The interesting thing to note is that the crowds are mostly unwilling to walk any great distances so if you hike out a bit you will discover wilderness without huge crowds.

Some safety considerations :

First and foremost, do not wander far off the marked trails without proper gear like a GPS, compass and maybe a topo map. It is very easy in many locations to get disoriented and totally lost unless you are paying close attention to navigation.

Second: you are in high dessert plateaus or canyons. Take lots of water if hiking. Invest in some Camelback or equivalent hydration packs if you intend to walk anywhere. Take more water than you think you will need. Dehydration is rapid and not noticed because of low humidity there. That can turn a nice day hike into a deadly situation quickly.

Cellphones will not have a signal in many areas there. Never rely on them for emergency calling in the wilderness areas . Satellite phones or emergency rescue beacons are the only reliable possibility of rescue.

Slot canyons have a unique danger most hikers are unaware of: thunderstorms in the area can cause instant flash floods that have killed hikers caught in the canyons without a way to get clear quickly. The storms may not be close to the hiking areas and the first warning is the wall of water rushing at you with frightening speed . Pay close attention to area weather forecasts anytime you plan on hiking into a slot canyon. If any doubt, stay out.

Finally : if you meet the age requirement (65) purchase one of the national park lifetime passes. Since you will be touring multiple national parks in the area you will save a bunch of money on admissions.

Have a great trip and stay safe out there 👌