I just returned on Oct. 5 from the Poly, and we stayed in the Rarotonga building. I would agree with requesting a first floor room for your mother, because the elevator was out of order at least one day while we were there. (We stayed on the first floor, so we were not affected.) I had requested a first floor room facing the quiet pool so that my little girl might get to see the ducks, and we were not disappointed! The ducks paid us several visits on our patio.
We loved the fact that Rarotonga is so close to the GCH and within easy walking distance of the TTC. Having said that, I do have to agree that our room smelled very musty and mildewy when we first arrived. I thought we were going to have to request another room due to the smell. But then I decided to open the patio doors and air it out for quite a while, and this really helped. After that, it simply smelled like I would expect a hotel in the Florida humidity to smell, so we did not change rooms.
(As far as the rooms being "run down", one of our bedspreads had a large hole in it, but that really didn't affect our visit.)
I also spoke with a couple of people staying in the Tokelau building (which is also a good location) and in the newly refurbished Aeteoroa building, and neither of them had noticed a musty smell in their rooms. (However, the lady in Aeteoroa had to request a room change, because the people next to her were chain smoking, even though it's a non-smoking building!)
We thoroughly enjoyed our stay at the Polynesian, and the housekeeping manager (Jeff) was really great to bring my daughter a stuffed Minnie Mouse and an autographed photo of Minnie when he found out my daughter was confined to the room sick with a stomach virus.
However, personally, I think I will request the Tokelau building next time, or perhaps by the time I go again, the Rarotonga will have been refurbished.