I have a custom offline terrain for the beta and then AH3 to practice gunnery land, sea, air. I used it to create a photo op where I placed all of our rides in the game down both sides of a runway, then parked them all together on the giant marsden matting re-arm pad in the beta single runway small field.
Normally I get 50-60 FPS. To take the photos and create a film to pull photos from, my FPS dropped 15-20 flying and driving by them. And all of the textures and color from surrounding tiles washed out or defaulted to sand. Your intentions are good but, the reality of technology bites big chunks with no exceptions.
All of that sand is grass not sand. Eye candy comes with a stiff price.