Reality: almost any decent size 24 if all your camping involves electrical hookups or just overnights without hookups. If you are dry camping or boondocking (no hookups) for more than a night, then a little more planning and probably some modification is wanted. In dry camping and boondocking, your unassisted battery runs out long before the propane or water runs out.
We wrapped a bicycle cable lock around our battery after hearing another story. Much cheaper than a new battery. We also take battery in for winter storage so no surprise in the spring