Tip for having three indoor kittens in the house without losing your mind: create a "kitten-proof" room. It's like kennel training a puppy, only with a bit more space. At our house, it's my "laboratorio," my work room where I draw, paint and write.
Keep one room where they can't climb on or destroy things you don't want climbed on or destroyed. Keep their litter box and food and water dishes there, on opposite sides of the room. Include a comfortable corner for napping and lots of toys. Make sure they're comfortable and happy and used to being in there by keeping the door open all day and making that room the feeding room. In their little kitten-brains, this means it's not a punishment or time-out room, but just "their" room. Cats are pretty territorial, and they will quickly learn that this is their place.
In the evening, when you've had enough rampaging for the day and they're getting on your nerves, you can put them in their room, give them some dry food in a bowl to eat at night and a little pat and kiss each, turn out the light and close the door, taking their "day dishes" with you. (Make sure that anything that might get turned into a hockey puck - anything small enough for them to move - is put away on a high shelf or in a box or drawer.) They can rampage all they like in their room because you've made it safe and a place they associate with food and comfort where they like to be.
In the morning, you can get up and make the coffee and get their food ready on the day dishes that you took away the night before, all in peace, without having to fight your way through them or trip over them. Then, when you're ready, it's breakfast time for the kitties and time for the daily rampages to begin.
This method has really worked for me and the Kitty Crew, and they seem quite content to be "tucked in" at night. Sometimes they rampage a little more after lights-out, but they very soon settle down, usually all in a big pile on my desk chair. Because I've never let them stay out in the common areas at night, they don't expect it and don't sit in front of the door meowing at all. I sometimes hear them start playing early in the mornings, but I don't hear them meowing to get let out until seven or so.
Guests who've come to stay have asked if this is going to go on, and I think probably not, but as long as they're still kittens we'll keep it up. Grownup cats need less of this, but it's a good idea to get their habits settled early. We'e been doing this since they arrived in May. Four months may not seem like much to me, but for them it's their whole lives. I read up on kitten psychology and everything said it's a good idea, mostly for your own sanity, to teach them to sleep when you sleep, and to teach them by consistent repetition, that your bed is not their bed. They're not allowed into my room as a result (though they keep on trying... nothing entices a kitten more than a new space and Henry is one fast and devious little bruiser!). They also know that there are certain rooms they're not allowed into, which is why I don't feed them in the kitchen - too many ways for them to get hurt or break something in there.
As they've grown, I think they have learned to feel safe and happy with this method, and I certainly appreciate sleeping at night without them deciding to make me into a human trampoline.
And yes, we do go outside, but only when I can supervise them. I'm terrified of that road, which is the main one leading out of town into other small towns through the mountains. People drive insanely fast on it, and it's especially busy in the summer, of course. I've already seen two cats dead on the road right outside the house, one a tiny kitten which I had to remove, and the other was one of the feral cats who live in the country shrubbery who used to come round regularly, and whom I used to feed now and then. I can't tell you the knot in my gut I felt when I stood by the window getting my breath of fresh air very early one morning and saw a cat I knew lying in a small pool of blood on the road. There were lots of kitty-kisses that day.
We have gone outside most days for an hour or so, and they really love it, and have so far stayed away from the road, but I'm dubious about just letting them out by themselves. They love to charge around like maniacs, and don't think at all about possible dangers. I know I can't keep them inside all the time; cats gotta cat, but that road... I not sure what to do, but am mulling over the possibilities. Maybe some fencing. Not sure.