RWT can have maps of different resolutions.
Actually you will always have maps of different sizes, because the textures have a size of 2 ^ M, and height maps have a size of 2 ^ N + 1.
M can be not equal to N.

You note that RWT can import RAW height maps and suggest it can import RGB maps in the same way.  That is, you seem to indicate that it is possible to import aligned RGB color along with a height map.

Does RWT allow these height and color maps to be different sizes?  Can World Creator support importing a higher-resolution color map relative to the height map, so that the image map adds high frequency detail to the lower frequency height map?

No, RWT does not support GeoTIFF and custom aerial photos.
But you can achieve it in another way.
After generation, export heightmaps to RAW file.
Open it in the photo editor.
Modify the heightmap image based on your GeoTIFF, and import it into RWT.
Exporting and importing RAW data is a built-in RWT features.
In the same way, you can use your aerial photos.

Two connected questions --

1.  Could you confirm the maximum topology resolution for RWT?  As I wrote, it looks like 10m/pixel from Bing elevation data, but it would be good to confirm.  If location matters, I'm looking for data for the state of California, in United States.

2.  Does RWT import GeoTIFF height maps and support texturing them with aerial photos?

Thanks again.

Unfortunately, you can not use LiDAR data in RWT.

Yes, you can use Mesh to Terrain for these purposes.

Real World Terrain generates the usual Unity Terrains, which WorldStreamer can use without any integration. Integration just a little bit helps make it more user friendly, and work around the bug in older versions of WorldStreamer.
You can use WorldStreamer with terrains created by Mesh to Terrain without integration.

We do not have special documentation for WorldStreamer, because in RWT it's only one button. The rest of the work is on the side of WorldStreamer.

Meshes from USGS ARRA LIDAR data have a claimed vertex density of: ~14.16 vertices/m2: (e.g.:  http://opentopo.sdsc.edu/datasetMetadat … 4.32610.1)

That would seem to give the ARRA LIDAR survey more than two orders of magnitude better spatial resolution, and DEMs from the same data have about the same sampling.

If that's the case, could 'Real World Terrain' import from the above USGS data?

Or should I instead convert the higher-resolution raw point clouds to meshes on my own and then use 'Mesh To Terrain' to create tiles?  I see WorldStreamer integrates with ‘Real World Terrain’ -- what is the extent of this cross-functionality?  Is there any documentation on tiling a large model for 'RWT' using WorldStreamer?

Thanks in advance for any help!

-Kevin

The careful reader may detect that my question presupposes that there is a benefit in translating from meshes to height maps (Unity terrains).  That seems reasonable to me, but I welcome any notes about experiences that suggest otherwise.