It's been quite awhile since we've used the community laundry at OKW, but I believe it's in the building between the pool and the Conch Flats area - near the shuffleboard. They definitely sell detergent in the main store at OKW.
As far as detergent. I can currently only speak for the studio at VGF. They had laundry liquid detergent in closet by kitchenette area. Haven’t been to OKW if supply it in their studios. Laundry areas near the pools.