I am not sure, but I think that they have soda at the bar area just off the lobby and in the restuarant area. They it all set up with cereals, coffee, fruit, etc in the morning and I am pretty sure they had soda machines there (I am a coffee freak, so I am not POSITIVE about the sodas.) FYI...this little set up seemed highly disorganized and it was more of a cattle call, IMHO. If all else fails, ask one of the Cape May servers to fill it for you. One of them was happy to help me out when I was in desperate need of my caffeine fix and the line for the bar/breakfast to go area was insane!
As far as the mugs being worth it....if you drink alot of soda, they are. Also think about how much time you'll be spending in your resort area, as they can only be used there! (We were lucky enough to have very understanding CM at the BC...they refilled our AKL mugs with no problem, as we did 3 days at each resort.)