With such a lightly stocked tank, when you do get the chance to go away, I think you would be ok if you tried to build a little more natural food in the tank. Big fish can easily go a couple of weeks without food but I'm always more cautious about smaller, more high energy fish, like cpd's. You could build up a little corner of botanicals in the months before you are away and introduce some more life to the system. You see this approach when breeding small fish like pygmy cories and it does work well. I did something similar with some fry I was raising and there was so much life, enough for constantly fat bellies, that I didn't need to feed the tank all summer long.