How do I make Vehicles?
The Short Answer
Adding a vehicle to your RPG is fairly easy. The OHRRPGCE already has predefined vehicle types for the three most commonly used vehicles: Airship, Boat, and Speeder.
A vehicle is just a special NPC that your party can ride on. To add a vehicle, go into the map editor, open the map you want to have a vehicle on, go into the NPC editor, and make a new NPC. All you have to do to turn an NPC into a vehicle is to set its Vehicle property to one of the vehicle definitions.
What about controlling where a vehicle can park? Go into the map editor in wallmapping mode, and press A to mark places where airships can land and B to mark places where Boats can dock. (A and B tiles can have other meanings if you make your own custom vehicle definitions)
The Long Answer
Read the HOWTO chapter on vehicles.