KGNF would indeed be a very good airport for testing and learning, as you have some excellent quality aerial imagery available there in Google Earth / Google maps ...which happens to have been captured during this same Fall season of the year.
Assuming you were going to use that aerial imagery only for your own personal purposes, and did not intend to distribute it publicly, you could easily make this in
SBuilderX.
The resulting custom photo real aerial imagery BGL when compiled, would be roughly 270 MB if it utilized the available zoom-level 18 which is the equivalent of 15 cm per pixel resolution (high quality).
Interestingly, it appears that the available aerial imagery for that particular airport area is actually capable of supporting 7.5 cm per pixel, unlike other areas in Google Earth / Google maps wherein the usual optical maximum zoom-level 18 aerial imagery has been digitally magnified to a artificial zoom-level of 19; so if you wanted to, you could actually make the aerial imagery at an even higher resolution than the zoom-level 18 ...which I utilized to test that area.
Once the custom photo
-real aerial imagery BGL has been created using
SBuilderX, that file can be opened using P3Dv3.x Autogen SDK Annotator to manually add Autogen object placements.
Alternatively, you could utilize
ScenProc to scan and detect vegetation and buildings from geo-referenced copies of the aerial imagery for your project area to create Autogen annotations semi-automatically.
Additional steps can be taken using
SBuilderX and a graphics application to implement various masks to blend the custom photo-real aerial imagery into the surrounding default land class textures, and also to precisely define the Grenada Lake and Turkey Creek water bodies nearby.
There are a number of detailed and relatively easy to follow tutorials available here at FS developer and at other FS-related websites to guide you through this process; if you are genuinely interested in pursuing this project, feel free to inquire further here in this thread.
GaryGB