Well I posted this thinking it was not a great idea but the subtle feedback I am getting here is that it is a BAD idea....
I think one thing I will seriously do is install another (non externally keyed) deadbolt near the top of the door. It would be very hard to kick a door open with two deadbolts and a regular lock.
I do have a small, but really loud, dog which I believe is a decent deterrent. I have an alarm system but I agree with another poster that the response time is long compared to any personal danger a person may be in.
I think the best thing to do would be to train her. Keep the guns in the gunvault (one of those quick key types) because the kiddies are still a little two young for firearms training. Somebody kicks the front door:
1) Grab kids run to bedroom and lock door.
2) Get gun from safe by bed.
3) Call 911.
4) Yell I've got a gun repeatedly??