Let's be serious here, you're never going to have just 1 item. If you did, a cast iron skillet would be hard to beat. A cast Camp Oven would be even better, but it's big and heavy. I love mine, but it only comes along in the wagons.
If you are going really minimalist, then you'll be cooking on a wood fire. that basically means iron/steel cookware as opposed to fancy stuff like stainless or aluminum. A wok is not a bad choice, but then a skillet is more traditional in the USA. It's also easier to throw in the fire and cook there. It's much better for pan cooking steaks or other meats, too.
A wok excels at stirfry cooking, but for the things you are likely to eat, while camping, a skillet is more practical. If space an weight are not an issue, then a Dutch Oven with feet is impossible to beat.
You'll still need something to heat up water for coffee, unless you really evolve beyond all your vices.
I buy my camping cookware in thrift stores. Go there and see what's available.