As far as gear goes, I'll tell you what I told my cadets (MS I class, University of Hawai'i).

-Don't bring a Rambo knife. You going to use a knife to open MREs. A modest size Swiss Army Knife (not the ten bajillion blade model) or a multi-tool (like a Leatherman or Gerber) works fine. If you go this route, get something with scissors; trying to trim moleskine with a knife doesn't work.

-Don't bring a $120 flashlight so bright it causes retina damage at 15m. You're going to use it to find your sleeping bag or check a map on night land nav. If you just CANNOT live with the Army issue flashlight, get a small (AA or AAA battery) LED type light with a red or blue LED.

-Wear a watch. Assume you'll lose or break your cellphone doing landnav and tactics. You'll still be expected to be on time, and an alarm is useful (but silence it during tactics). A G-Shock is an excellent choice.

-If you're not issued a poncho liner, you might consider making this investment in your career. Your wubbie is your friend.

Concur with the long underwear; a good set of polypro can save your life. Or at least prevent cold weather injury (not a problem for my younglings though).