Hi Doug,
I don't usually use IS to put in ground polys, however, the landclass of the scenery & terrain.cfg determines the final poly texture display when you choose one. Since these have both been customized by ORBX, there will be a number of land classes textures that do not match the default.
Unfortunately, IS sets up its own engine for creating scenery including a temporary default landclass, so you see the default dirt texture when the IS engine is running, but when you restart without IS you are seeing textures generated by the customized ORBX terrain.cfg/landclass. Bottom line, the default LC131 (Dirt) poly texture has been reset to golf courses by ORBX for their own needs, at least in SAK. There are only so many landclass numbers, so ORBX and any other extensive developer has to overwrite unneeded default landclasses with their own special needs. I have checked it out on my system along the pipeline and the default dirt poly texture shows up as golf course under the ORBX configuration.
I think the two airfield land classes (LC139 Airfield 1 & LC140 Airfield 2) work properly in ORBX Alaska, so try one of them. Of course, photo real overlays could be used also to produce real looking dirt but that takes more time and skill.
Rod