Ding Ding Ding- We have a winner! I am confident to say this mystery duck that I saw at Four Ponds Conservation Area in Pocasset, MA is a female ring-necked duck.
Source: Lloyd Spitalnik's Wildlife Galleries
http://www.lloydspitalnikphotos.com/
Leah at BlueBirdFriendliness gave me a good tip about Scoters and Eiders, and I was fairly confident that it was a Female Common Scoter in 2nd year breeding plumage, but the ring on the bill was lacking in the pictures I found.As my friend Dave always tells me, if there is a key characteristic missing then it probably isn't a match and keep looking. I should have known better but didn't think I could get any closer.
Thanks to Andy at Andyslens.com for helping me solve this mystery! I better study up and spend more time outdoors so I can get a little sharper.