The Hunter Manhattan Burning Route is one of the most difficult Burning Routes early in the game due to the fact that the Manhattan has tank-like handling and the route takes you through areas with dense traffic.
At the start cut through the building under construction, then through the park. Once your out take a left onto Root Avenue, then an immediate right under the train track onto 2nd Street. Even though it looks so inviting, make sure not to take the jump onto the train track. You will not be able to get off until the super jump and will miss the turn. Go up a block to Fry Avenue and take the shortcut on your left, thus leading you to Harber Street where you can then coast the south of Paradise City until you reach the Naval Yard. Using Manners Pier is always a good idea as well.