I was bored so I made the Chicago field on google SketchUp. To preview the field here is the link.
After you have instaled the program go to..
File-> 3D warehouse-> get models-> seach 2011 NPPL Chicago
When the file has loaded go to the CAMERA tab then WALK
the arrow keys allow you to walk around and if you hold the shift key you can side step and move vertically. Also, when in walk mode if you type 3' or 5' it will put the camera at that eye level to simulate standing or crouching.
Notes: I dont think the small doritos are quite right but its the best i could do for now. The layout and bunkers otherwise are all accurate according to nppl.com and supair. Let me know if there are any changes that can be made, if there are enough i will make a revised model