First, I would say that I'm glad to see you are thinking about it. Certainly step one. If you don't feel comfortable and your husband can't convince you to change your mind, then you are talking about a VERY specific situation in which he has been incapacitated while leaving a loaded gun behind. Chances are pretty slim, but so be it.

Second, I think you should address your estimation of yourself. My wife can sometimes come across with the same idea that she wouldn't be up to the challenge. I've found that having a child changes my mindset and I've seen it change hers. People can and should defend themselves with everything they are willing to use. Adding a child to defend into the mix makes this even more true.

Third, for you I would be less worried about an unarmed gun left behind and more focused on how you can improve your chances without it. I recommend taking a Women's Self-Defense course at your local gym/Y/shelter/sherriff's, taking martial arts (our class often gives Women's Self-D seminars) and generally rethinking your ability to disable someone who's bigger. I've seen a 90 pound 15 year old stop a 30 year old who was more than double his weight and probably 5 times his muscle mass. Do NOT count yourself out.

Sounds like you have the main stuff covered - alarm, secured house, etc., Dogs are good and Neighborhood watches are also not a bad idea. The only thing I'd really like to see you do is change your attitude... it seems like a "victim's" attitude. I should mention that criminals often pick up on that vibe since it spills over into actions and how you carry yourself.

Oh, and a whistle directly into an assailant's ear can incapacitate and startle enough to get away. It's just one of many non-lethal options open to you. So maybe research what you are comfortable using (especially in an enclosed space).