Just came back from a stay at the Yacht Club last week and I must say it was wonderful!! We had the dining plan for the 1st time and we weren't sure either what was available but it worked out fine. If you use a CS for breakfast, you can go to Ale & Compass at the Yacht club. They have a small selection of bagels, croissants, muffins etc. and you get 2 drinks with that. I would get a coffee or sometimes cappuccino and a bottle of water to take with me to the parks. Over at the beach club there is the Marketplace with more of a selection of pastries etc. and they also offer an egg (& cheese) croissant (with 2 drinks of course). For lunch, you can go to Hurricane Hannah's by the pool and they have a selection of sandwiches and "cool" desserts (ices, ice creams etc.). Not sure what the Marketplace has for lunch (never made it in there at that time). If you don't mind a little "traveling", we found the Boardwalk Bakery (over at the Boardwalk hotel) a great place for CS lunch. They have some good sandwiches (and a GREAT chicken caesar salad). The best thing is that you get to pick ANY dessert from the bakery. The carrot cake is to die for!!!
Also, the refillable mug can be filled at the Marketplace, Hurricane Hannahs, Ale and Compass and Beaches and Cream.