Although the SimpleMap WordPress Plugin was originally created for to help content creators and site owners map out store locations, I recently helped a ministry implement this for their multi-site campus locations.
Needless to say, it worked like a charm.
With an easy-to-use interface, you can add “locations” with a few clicks of a button. Instead of “stores” they’d be your multi-site locations.
It can pretty much work right-out-of-the-box as long as you have a Google Maps API key (which is easy to get, go here).
Check out their website, some of the demos they’ve got going on, screenshots, and then download it if you’re a multi-site ministry leveraging a self-hosted WordPress install.
Booya. Love it.