Some of the smaller agencies I'm working with are regional in scope and it is likely end users will not have an address at the destination (and maybe don't have a start address they are particular about during an investigation phase.)

Currently Google Transit(GT) uses the centroid for the city if all you give for a to/from field is the city and state. But the centroid could be far from the optimal start/end point for an inter-city trip.

Perhaps GT could detect that a long distance trip was being planned and fall back to a different method that would first find the optimal trip between cites and then assign the to/from addresses?

This case is complicated by the fact that the GT feed files in the two cities may not be the same set of files.