I put “camping with oxygen cylinder” into Google & there are useful threads written by people with direct experience. (Some were American & less relevant.) Talk of rechargeable compression machines that take O2 out of the atmosphere, using O2 cylinders only as backup; the need for a sticker on the vehicle to alert emergency services etc.
But in short, it’s certainly do-able. I think one person was still wild camping in a tent.
We watched a mum of 2 smallish children put up a tent and set up, she had a portable oxygen set up on a trolley. She unhitched briefly now and then, but otherwise seemed to cope very well.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.