The best way to figure out how to make maps is to open the outskirts.map in any quake 2 map editor. The outskirts.map can be found in the speedway/maps folder when you install Speedway.
The only entities that are needed are "track_info" and "track_marker". Look at the outskirts.map to see how those are used.
You may also make deathmatch maps. If you set the laps to -1 in the track_info entity, then the game will run in deathmatch mode and it wont end until the fraglimit is hit.
You may also create an enitiy called "map_model" to add md2 models or sprites to your map. Create an entity with the classname "map_model". Then set a field called "model" with the path to the md2 or sprite and set the number of "frames" if it has animations.
If you have any questions about making maps, please ask on the forums.
