Quick Start For 2000 x 2000 Tracks
On teh left hand side you can get a starting base terrain for your 2000 x 2000 track. Just create a new track & save it then close the editor & open your .trk file. copy the code from the your selected terrain & patse it into your .trk file after the lightmap line
once you have done that save the .trk file & load the track in the editor & once it loads you should see that your track has been filled with your chosen terrain.