must haves for me would be...
a reliable vehicle to get you to and from where you are going
something comfortable to sleep in and on (could be a swag, tent, camper or caravan...it doesn't matter to me so long as you're getting out there), aswell as something that keeps you warm in bed when it gets cold (you be the judge of what this is...lol)
decent shade from the sun and cover from the rain, both when sleeping and during the day....nothing worse then getting everything wet when camping or baking in the hot sun
something to keep the food and drinks cold...we had an esky for years that worked fine, these days we have a fridge
some good night time lighting, LED lights for us now with the camper though a simple gas lantern did the job for us for years when all we had was a tent
a comfortable chair to sit in and something to cook on (fire or stove i don't care as both work fine)
after that the rest aren't essential / must haves...more like luxuries / stuff we think we need to enjoy the outdoors more but likely don't really need. We had just as much fun camping years ago without all the stuff we take away now, so who is / was doing it the right way...me now or me back then?. At the end of the day it doesn't matter, it's just good to get away and relax one way or another.