I could be wrong on this as hotels in Playa Dorada can change their names fairly quickly & regularly BUT, .... I think you refer to the hotel that WAS known as Dorada Naco a few years ago. It is the hotel in between Playa Naco & the Plaza. There IS beach access from there by going down the pathway alongside Playa Naco hotel.
YES, public can visit Playa Dorada complex but be aware that in Semana Santa there is usually a one way system round Playa Dorada (in one gate & out the other) PLUS watersports at the beach are discontinued! It will also be extremely busy!! Regards ~ Grahame.