Forces already invest significant time and energy communicating with their workforce, usually via force intranets. Email-newsletters can be very cost-effective additional way of getting your messages across.
There is a wealth of content already produced in forces, some of which would be suitable for sharing with an adult family audience and potentially some of which may be suitable for children.
Forces could consider developing a family specific newsletter incorporating some of the content that already exists and sending a link out via email, the website and social media.
A newsletter could include a Q&A where the force responds to commonly asked questions or concerns.