As discussed.

This is the current problem:

Proposal A: calculate on demand
Solver's score calculations call to Location.getDistanceFrom() call graphhopper etc

Proposal B:

Locations that are already in the database, but not yet distance matrixed are called FRESH.
When a fresh location is distance matrixed it will be REJECTED if it doesn't not connect to all of the other locations.
Otherwise, it's CONNECTED.