The only convenient way to export TG2 terrain data to non-native (.ter) format is the Heightfield to LWO node. You can also use the LWO Micro-exporter, but both export geometry. The .ter format is a heightfield format, virtually equivalent to a displacement map, and if you used Terraconv (
http://koti.mbnet.fi/pkl/tg/TerraConv.htm) to convert to 16 bit TIFF you could probably use that as a displacement map in Maya, however .ter export depends on the terrain being a heightfield. As far as I can tell the Heightfield From Shader node isn't working properly (or consistently, at least) at the moment, otherwise I'd suggest using that first, then saving a heightfield.
In any case if your terrain *is* a heightfield, or you can get the Heightfield From Shader node to work, then all you need to do is right-click and Save Terrain As to get a .ter, then use Terraconv to convert.
Better import/export options should be available for the final release.
- Oshyan