Here are somel thoughts.
The Range of a tiny baby rattler is quite limited 5 or so miles; it could stretch since the range would not encompass Territorialism.
A momma rattler does not have just one baby, and she bears them live! She can only reproduce once every two years of her life.
She will become active with a male (her choice and time) in the Fall, and then by Spring she will begin to gestate the young for 90 days. Given this, your little rattler was probably born in March or April. He might not have gotten out and about too much until May!
So, given this fact, you can be certain that he was born nearby and that his siblings are nearby.
Please do not take this the wrong way. The reason I am saying this is because I think that this is the time when the kids need to be exposed and taught the whole truth about a Rattlesnake. Did they get to see it alive?
You see, a Rattler is such a specialized Predator that it knows what you are; and what you are is not anything it wants to eat, kill, or come after! It is quite the opposite effect really. We smell (or to a snake, Taste) like soaps, chemicals, and other such nasty things. A Rattler can differentiate you from the rest of its world of animals.
So, with enough understanding, you can gain a deeper
appreciation for this incredible creature! Seriously though, the cases of 'Plague' are on the rise, and the CDC has gone public that squirrels, mice and other rodents, and such are Carriers. Several cases in New Mexico, California, Arizona, and now an entire Prairie Dog colony in Colorado is off-limits to people visiting.
As well as the Bubonic Plague, mice are also carrying the
Hanta-Virus which can kill you just by breathing in the dust from the mice droppings.
It is easy to change our own Parameters..our own Paradigms. The snake is just a snake and doing that wonderful thing that snakes do...eat small furry pests! We change our thoughts about them and then they can coexist with us. We become aware of them once we realize they have always been aware of us!
They are Nature's Defense!
Huggs, Ron
Here is what you should do in my opinion, since I have seen your property and it does appear to be the perfect setting for snakes.
Around the perimeter of the kids area and the living area of gardening and such, you should take a post hole digger and place a single hole with a flag at strategic points. I would say 20 feet or more apart. Flag them so no one walks into a hole. Then every few weeks when you are working in the yard walk the perimeter and look in the holes. These would be about the size of a standard post hole.
Snakes will naturally go into a hole space to check it out, and once in the hole (make it several ft deep) they sit comfortably there until something drops in on them! Most times they can get out of the hole, but during those cooler early mornings they just sit and rest until they warm up. So morning checks are better.
You will need an extension pole with a hook to manipulate them. Place them into a pillow case or burlap bag and then transport them to a new location. I bet the kids would love the whole 'Operation Snake Patrol' LOL

They might even find some other fun things too!
Wishing everyone Well and make this a great learning tool!
Here is a nice website from the San Diego Zoo
http://www.sandiegozoo.org/animalbytes/t-rattlesnake.html