For those of you who haven't figured it out yet, the haulers are a mini-game found in the Kirlsa Caverns. The control panel I speak of is near the entrance of the area you get to if you go right from the entrance to the caverns and go through a short passageway. But you can't use the haulers to get through the caverns until you have pulled a switch in the northern room, which is directly to the west of the healing and save points that you get to if you follow the rails around east-north-west of the control panel. There is a boss you will need to defeat in order to pull this switch.
Controls
Accelerate : Press up on the control pad.
Decelerate : Press down on the control pad.
Switch tracks : When prompted, press right or left on the control pad, and make sure you are traveling at less than 25 km/hour.
Stop : When prompted, slow to below 15 km/hour.
Jump : When you come to a jump, make sure you are traveling more than 25 km/hour.
Hauler Types
Steady : Can be controlled, but accelerates VERY slowly. Has medium endurance. Use this one if you want to collect the treasures VERY SLOWLY but surely.
Carefree : Will turn right, right, left, right, always carrying itself in the same exact circle back to the entrance. Accelerates not much faster than the Steady Hauler. Has high endurance.
Whimsical : It follows no commands, but accelerates rather quickly. However, this Hauler is the only one that can get to the Earth Pixie found in the southwest corner of the map, because it is the only one that can jump that far. This Hauler can accelerate very quickly, and has medium endurance.
Ill-Natured : This one will always choose the opposite of the path you give it. It has low endurance. It can be better than the Steady hauler for just collecting treasures, since it has high acceleration, as long as you remember to give it the opposite commands.
Aggressive : May or may not obey commands, and will not slow below a certain speed. It will not stop, so it can only be useful for breaking down walls, as none of the other haulers can do this. It has high endurance.
How to Complete : Ride on the Steady Hauler. Choose the following paths: left, right, left, left, left. You will get to Gregory.