Gas station is not great because people generally don't like being approached; they think you're going to ask for money, ostensibly for gasoline. It's also more difficult to target people going the direction you're going.

Truck parking might work if you're looking to get to the opposite coast, but a trucker isn't exactly going to be super amicable about dropping you off in the middle of the metro center of the next city over. He's got a schedule to keep.