Trinity would be a completely different map if the border mountains were turned into border hills and this would be really easy to do in the terrain editor. There is a text file that accompanies each terrain that gives the highest altitude in the terrain. All other altitudes in the terrain are scaled from that one number. So all HTC would have to do is reduce the number in that file to say half its current value and all land would be reset to half its current alt, including the border mountains. This shouldn't need any testing either, as potential bugs like too steep slopes for GVs or mountains at the end of runways will be reduced. Also flat terrain under objects would remain flat, just half the alt of before.