@poppa terry, I do maintain a sourdough starter and bake from it often, but i’ve never made biscuits so I don’t think I’d be any help with a recipe- hopefully others will chime in there!
As for refreshing, I recommend a trial run or two before you go. You may be able to get away with a once daily feed in the morning, with enough flour for about twelve hours fermentation. The nights sound like they will be somewhat like a refrigerator, so store the practice starter in the fridge at night and make biscuits in the morning.
You can measure out the flour in little plastic bags before you go, and I also recommend an emergency kit of a little commercial yeast (if your biscuits are yeast-raised) and a little salt (to be used if temps are warmer and the starter is fermenting too quickly).
Another thought- you could make baking powder-leavened biscuits and use powdered buttermilk or dried mature starter to give them flavor. Then all the variables of time, temp and feeding will not be a problem.
Have a good trip!