I can't remember if this is nearer to Ensenada or Rosarita but we've always loved El Faro Beach. It is right next to the sand and very low key. The only thing is, the last time we went, for some reason the sand was all washed away so it was more rocks than sand so you may want to check on that. Also, right next to that one is Estero Beach which is much more expensive and not so low key but it was great, too. We just had to walk a little ways to the sandy part of the beach. It has a hotel on site and playgrounds, etc.