The Riverside Annex is a typical WWII bomber base. Several very long 300-ft wide runways. The area we are using, called the "X", is pictured above in David G's second link. In addition to the two wide crossing runways, there is a narrower taxiway that completes the triangle.
The surface has a lot of exposed aggregate in a similar texture to Lincoln. And there is enough space to easily do 90 second courses that are flowing and not slow. Yeah, it's big.
There is one obstacle...a small storage building is just alongside the one runway near the crossing. You can see it as a white rectangle in the pic linked above. Very easy to avoid with course design.