You can call the main reservation line to have a request put on your room, just remember that requests are not guaranteed.
We had a request at CBR this spring. It was important for us to me on the main floor and I was told by the main reservation line to call the resort the morning of to confirm our room placement and they gave me the number.
So, I got up extra early before our flight out and called and confirmed that yes, we had been placed in a main floor room.
But, upon our arrival and check-in, we were given a room on the second floor. It seems that our room was given away to another guest sometime during that day. If you want a specific room, be sure to have an early check-in time.