If I wanted to fight (or assist) in a limited war, I'd go for a solar-powered backpack, night-vision goggles and radios (x5), water purification, gold (for money), antibiotics, and a taser.

The trick, as a sibling commenter pointed out, is that you could easily spend 99% of your time getting water, finding food, learning to communicate, etc. You have to find a way to move beyond that point -- and that's a non-trivial barrier.

It'd be much better as a team of seven or so.