Pete, there's lots to consider here, but just a few suggestions...
It would be a good idea to WEAR the Glock 30 24/7 and not just keep it at bedside, and that would go for other members of the household you deem competent for armed defense as well. Cell phones on the person for everyone in the family when out and about on the property is a good idea, too.
Should the day come when you need your defense guns, it will be strong for you in court that the Sheriff's Department has advised those in your community to take precautions...but it will be stronger if members of the Sheriff's Department can testify that they personally helped you to arm yourselves. To this end, ask the Department if they can send a deputy to do a security assessment on your home. You'll get good advice on locks, alarms, and related topics, and the Department may by now have developed "persons of interest" and have descriptions of suspects that they can share with you. Useful intelligence, and it leaves you in a stronger position to defend your actions should something happen. Perhaps the Sheriff's Department can even arrange some defensive shooting lessons and use of force lessons for you and your neighbors, further establishing the lawfulness of possible future actions in defense of yourself and your family. I'm sure they'd be happy to help coordinate a rural version of Neighborhood Watch for you, too.
Your letter didn't mention details on the robberies, but if they're involving multiple home invaders, you might want to consider adding semiautomatic rifles to your home defense armory.
best of luck,