I also thought that CSR is changing over to queen sized beds, but I haven't confirmed that recently, just that it was in the works about 6mos. ago.
IMO, the trundle bed at POR is not an ideal bed.
I DID think the extra daybed in CR was very nice and comfortable. In my mind it's like a very nice futon. It folds out, and even with it folded out there was still plenty of room to move around.
I think the mod rooms are plenty big, but the extra space in the deluxe rooms is very nice - especially if you have multiple adults.
Another option is the cabins in Ft. Wilderness or a bunk bed room at AKL or (I think) WL. Then again, you could also go villas.