THe premium 1BR units are in all of the buildings. Oceanside are the units that are at the ends of buildings 100, 900 and 1400 facing the Caribbean Sea.
I haven't rode a bike there, but would agree about the sidewalks. They aren't in great shape. Also realize that Lagunamar is located in the Cancun Hotel Zone and is more urban environment much like Miami Beach. It isn't a nature lover's paradise.