Hola La Piedra. It appears there are 3 casinos in Mayagüez and one in the old Ramey AFB complex (next to the Marriott). The ones in Mayagüez include the Holiday Inn on the ocean side of the Rt 2; the Mayagüez Resort (looks like the former Mayagüez Hilton); and one in downtown city in what appears to be the old Spanish hotel. The later two have been there for decades. The prospects for success at a Rincón location are not very good (unless it was intended primarily as a money laundering exercise).
Cool, the one on Rt 2 is the one I know of, I have driven by it several times and meant to stop and try it out but ended up doing other things instead.