Hi Susan!
We love Port Orleans - Riverside, and have enjoyed many a vacation there! The rooms located in the closest sections of Alligator Bayou are going to be those 'preferred rooms.' When looking at a resort map, it'll be rooms in buildings 14, 15, 18, and 27.
There are standard rooms available in Alligator Bayou, and Magnolia Bend, but do keep in mind, some are Garden View, others Water View, as well as King Bed options as well in many of the buildings. Royal Guest Rooms, one of the fabulous
Disney Story Rooms are located in Oak Manor and Parterre Place.
I hope this helps you plan your vacation!
Have a magical time!
Amanda