How can I translate the actual location data?

The Locator doesn't provide for translation of the location data (E.g. the address, description etc) through Joomfish or similar language plugin.

To provide your locations in multiple languages, use the Tag feature to create locations by language.

For example, create a Tag called "German" and tag all locations with German translations with the German Tag.  You can then create a new locator, and select German under the "Tags" option. This creates a locator with only German tags.