Take the  local bus from downtown Puerto south to Boca de Tomatlan!  It costs only about $1. each, and takes about 40 minutes.  At Boca de Tomatlan,  it is quite simple to hire a local water taxi on the beach, for the boat ride to Quimixto.  Stop and eat lunch at Boca de tomatlan at the family run restaurant  farthest north along the small beach (clean and quiet!).  On the way to Quimixto, there is a  brief stop at Los Animas.   At Quimixto,  simply followed the main dirt road, on foot,  off to the left then inland, to find the horse rental location.  A local guide will go with you, the 45 minute horse ride through the forest to a waterfall!  This waterfall though interesting can be too crowded to enjoy.... the horseride itself, through jungly forest and conversation along the way with your local guide is the best part!!   Don't bother booking this trip through expensive "Vallarta Adventures" or other travel group!  Much more interesting to travel on local buses and water taxi!     Enjoy!