We did a split between POR and Poly in February. On the switch day, we planned to go to Blizzard Beach. We packed up our stuff, threw it in the rental car, had our backpacks ready for BB and headed over to Poly. When we checked in at Poly, I told the CM that we didn't need the room right away since we were going over to BB, so if waiting would give us a better room, we'd like that. He looked things over and said if we didn't need to get in right away, he could give us a nice room at Fiji -- just come back after 4:00. We got back about 5:00, and were given a gorgeous third floor room in Fiji overlooking the marina. (I paid for a garden view, so this was a wonderful surprise.)
Since we moved our own luggage, I can't tell you how the hotel transfers work. I've heard a mixed bag on that.