I would not ask to be over looking the Boardwalk. The Boardwalk is very congested with people jogging and headed over to the bakery beginning at 6 am. There are games at night along to boardwalk and tends to be active until about midnight. So if you are looking for more of a quite room, you dont want to be overlooking to boardwalk. Also, the are the boats that transport people from MGM to Epcot, stopping at all the boardwalk resorts along the way. These boats honk their horns at each stop and in my opinion tend to be louder when facing the boardwalk. Ive stayed at the boardwalk several times and think that a room facing the pool might be the best bet. Yes, the pool. Because...
1. We arent usually in our room during the time the pool is open, so we dont really hear any noise or kids playing.
2. With the cold weather Floridas been getting, the pool crowd might be a little less during your stay.
As far as calling the resort
I dont know. My Husband has always taken care of the reservations, so Im not sure if he asks when he books the room, or when we just show up. You may just want to call them now and see what they suggest. Never hurts to ask.
I hope this helps.