For this trophy to unlock, you will need to send a single land convoy to all three locations in one trip; Boston, New York and the Frontier.
In order to be able to unlock this trophy, you must first have reached Sequence 8 and visited at least one general store in New York. Once you have done that, return to the Homestead and access your accounting book. Move across to the trading menu and select one of your land convoys. Select a resource to send (it doesn't matter what, high or low value) to a store in each of the three locations.
The convoy doesn't need to make a successful trip, so the risk percentage doesn't matter. The trophy will pop as soon as the convoy is sent.