We ended up at the Fairfield Inn and Suites in Lake Worth Beach/Palm Beach (I think the border runs thru the property). Used points for 6 nights (buy 4 get 5 +1) and a certificate. No upgrade available, I don't think they really have any suite rooms, just extended rooms with a sitting area/sofabed.
It certainly wasn't fancy, but it was less than a 10 minute walk to a nice beach, which was exactly what we needed.
No resort fee and free parking which is key because you pay for parking everywhere in that area. They give you a slip of paper to put on the dashboard. $3/hour at the beach lot next door which was usually packed. Nice to leave a hotel after 7 days having paid exactly $0.
Considering we had no alternative anywhere if we wanted to use points, it worked out quite well for us. Place was not quite full on Wednesday/Friday, but packed beginning on Saturday. Lack of real suites and maybe no adjoining rooms meant many fewer kids running around than anticipated