I lived out of a tent for a couple of summers. Getting a gym membership was an easy way for me to have access to showers. At the time I mostly just ate food that didn't require cooking though I certainly could have used a camp stove easily.
I showered less frequently, but there are many options out there, such as:
Friends and allies, beach and camping showers, gyms, pirate bath.
I did not cook much, and just ate things like nuts, bread, and cheese. But I had a simple wood stove that runs on little sticks. (Look up rocket can stove.)
Generally speaking, for most things, it was just a matter of "stay calm and improvise".
I had a friend doing the van living thing, he was coming by every day or so to shower at my immobile home. It got kind of old and I told him he was going to have to start cleaning it once a week to continue on. He said fine. Then he proceeded to never show up again lol other than to drop by and say howdy.
