We just finished a 3 day full period immersion field training exercise. Patrols, digging fighting positions, sleeping and eating with no modern kit at all...it was awesome. Here's yet another reason to go FJ: sexay Luftwaffe tropical MC Hammer pants. You laugh, but wait until you're crawling in the dust at 30+ degrees: they are heavenly.
We just finished a shoot for a TV series, as well. Positioning yourself as a fully equipped, knowledgeable WW2 reenactor has lots of fringe benefits...