I''ve read that some folks have been able to convert CS credits to snack credits at resort locations (not in the parked or DTD). However it usually sounds like it's 1 CS credit is converted to 2 or 3 (less common) snack credits that have to used then - so you can't go to the resort and convert the credits and when go to the park and redeem them. A drink counts as a snack credit, so it's very unlikely that you'll get 4 snack credits for 1 CS credit.