Frankly, with your kids on a different floor, investing in a cheap intercom system wouldn’t be a bad idea. Hopefully they have a lock on their door.
Forget clearing the house till you’ve got the kids and everybody’s together. Also, depending on their age, make sure the kids haven’t invited anyone over!
You need to identify a safe room in your house where everyone gets together and huddles down till you figure out what’s going on. Generally this is the master bedroom.
However, if you and your wife are in the master bedroom and the kids are in there own bedroom, you might want to go to plan B and make the kids’ bedroom the safe room and join them there. That way the kids aren’t being drug through a house containing possible intruders.
The safe room definitely needs a phone. However, intruders will sometimes take an extension (say in the kitchen) off the hook, which prevents out-going calls. So you also definitely need to have a cell phone with you.
You also need a small, powerful flashlight such as a Surefire. My opinion is that if you’re using a handgun when doing a search, you’re better off with a separate flashlight. With a long arm, it needs to be attached.
If you’ve got a flashlight mounted on your firearm, remember that when you point the flashlight at someone, you’re also pointing a firearm at them.
Intruders will often leave a door or window open so they can get out fast. If there are two of them, they’ll sometimes open a second exit so they don’t bump into each other getting out. If you find something open that definitely shouldn’t be, it might be time to call off the house clearing, retreat to the safe room, and call the police.
Always, always, always remember to keep your finger off the trigger and to make proper target identification before pulling the trigger.
The NRA sells a 200 page book titled “NRA Guide to the Basics of Personal Protection in the Home” which gives a lot of good information re: firearms usage, safe rooms, giving verbal warnings, greeting the police, and such. It goes for $6. Unfortunately, it doesn’t cover house clearing.
If you are really serious about proper house clearing, get a copy of Gabriel Suarez’s “The Tactical Advantage”.
While it’s a tough call, I think you’re better off turning on lights (though try not to back light yourself) and not worrying too much about sneaking around (which you normally can’t do in a wooden house, anyway).
Actually, it might even be a good idea to call out “who’s there?” or “I’ve called the police” a few times.
If you can scare someone off without shooting them, by all means do so. Imagine your kids’ reaction to having someone killed in their house. (Also, imagine what that would do to your house value.)
On the other hand, your family comes first – and if that involves dropping a hammer on some intruder, so be it!
Just my opinions, of course, for whatever they’re worth.