We found it bes to drive over the bridge back around by the airport and out over Terres Basses through Marigot and just keep following the main road. Relatively flat this way. Going the other way through Phillipsburg involves traffic and large steep hills to go up. Have not been there since the new causeway was put in by the airport roundabout but that may make it even quicker going that way instead of out the Terres Basses route.