If they go the PotC route, you take the look, the feel, the setting, and a few scenes from the attraction, and flesh it out. Create characters that seem organic, like they could have been in the attraction for years. Give it a great unique storyline that doesn't contradict anything in the original, and allow the actors to develop unique performances and memorable characters.
oooooooooooor
Go the way of the Haunted Mansion. You take the look, the feel, the music, even a few show scenes and put them in a beautifull elaborate setting. Then stick a generic family in there with a generic "family pulls together" plot, and a ham of a comedian who just plays himself and mugs for the camera, pushing all the really interesting attraction-related elements into the background, into a crass obnoxious mess of a movie.
I think that the Jungle Cruise could be a great movie. Give a us a funny sarcastic skipper, surround him with unique memorable characters, a 1937~ish time frame, a villian that we love to hate, and pack the whole thing with cool set pieces and action taken from the attraction. DO NOT make a "family movie" about a bunch of plucky kids who defeat an eeeeevil land developer and save the rainforest with the help of a cute monkey sidekick or talking parrot.