In the Detroit, Michigan metro area I know of only 3 places that you can fill an NG tank.
A gas station (Marathon) on Schaeffer just north of the Fisher freeway
Another station out near Metro Airport (Alas never been there)
And if the side of your truck has the proper corporate logo... One company pump (The gas company... Naturally).
As for gasoline.. Accross from the Marathon is a BP. down the road is SHELL (not a station, the But the refirnery, Also the Marathon refinery and one other) and that's all within a couple blocks. It would be hard to drive a Mile on a primary road without finding a gas station. And most of those sell Diesel as well.
That is the big problem with "Alternate fuels" Finding places that actually can re-fuel you. In time, this will be solved, but not yet.
For a fleet of LOCAL delivery vehicles.. The company pump concept works.. OH, one more place that pumps LNG is the Detroit Department of Transportation.. The drivers of the LNG buses get special training in what to do in the event of fire. It is not a nice fuel when it burns,, Propane is much nicer or so I'm told.. I've ridden those easiely identified buses (They look like trollies)