Currently it is almost not possible to get the path to the surface texture of a map.
A way for A3-Maps is to parse the surfaceType, parse out the leading # and search for the file name in the CfgSurfaces. Afterwards this can be combined to a full path of the surface texture.

However this is not so easy possible to community made maps as the paths are differing. The configs defining the surface textures are baked into the map making it impossible to dynamically determine the surface texture path.

It would be nice if there would be a command like getSurfaceTexturePath <position> which returns the full path to the surface texture. This would allow dynamic retexturing of objects to the surface texture. A common example for this are trenches added by ACE which have the same texture on every map. This is not only unrealistic, it is also really ugly.