The list of what cadets will need for Field Training is in the AFROTC Field Training Manual pgs 25-28 (just google 2013 Field Training manual and download the PDF). POC in my detachment have recommended buying good boot socks (with extra padding than the issued ones) to avoid blisters. Also, it is actually against regulations for GMC cadets to wear non-issued boots (Reference: AFI 36-2903 AFROTC Supplement), but I did buy insoles for my boots and they make them so much more comfortable! Another idea is a second good pair of running shoes. I got shin splints last year from running in cheap shoes so I got a good pair of running shoes, and recently got another pair for field training when they were on sale. Just they can't be any flashy colors (grey, white, black are best).
Hope this helps!
Hope this helps!