Have you considered seal a meal bags with wet kraut portions? I watched "It's Alive with Brad" on Bon Appetit doing ferments in seal a meal bags. The kraut might ferment more but if your outside temps aren't too high it might be a way to keep the bacteria thriving. Maybe a spring and fall backpacking solution. Also they have portion size bags of like a pint or a quart on Amazon for a decent price. You could easily pack individual portions.
