I don't think new currency systems are really needed. Just make camp supplies drop from combat and quests, and reduce the amount you find in random containers.
100% this! Don't give everybody and their brother a full night's camp supplies. Don't have so much food around that it becomes trivial to loot more than you'll ever use. (Obviously, I hope, reduce the number of containers to waste time looting, while you're at it).
The current camp system is really not that bad, but would be improved by food/camping supplies being valuable, not the year's worth of potatoes, sausage, and (likely rotting) fish I'm schlepping around. Maybe give some of this food expirations - fish only stay edible for 20 turns, fresh meat for 25, and so on.
