An average day riding on KCOL for me is in the 50 - 60 mile range, sometimes even a lot more. However, I do put in at Coleman Landing on the south end of the lake so that adds around 30 miles right there. With my car motor boat, I get around 2 mpg. I can get close to 5 mpg with my sled if I don't get into the throttle too much. Even if I'm playing around I still get well over 3 mpg. It's a good idea to track fuel usage on your boat both to answer questions like yours and also a sudden or steady increase in fuel consumption can indicate something going wrong in the engine. JMHO Anyway, if you are riding out of Camp Mack, I would plan to have enough fuel on board to run at least 40 miles.