Reminded me a lot of the film 'Loch Ness' (1996)

The similiarities:

1: The hunt for a 'fabled' animal in a remote setting by a scientist character with a dubious motive;
2: The development of a relationship between the scientist character and his boarding lady (who is widowed);
3: The child of the boarding lady has some knowledge of the location of the creature being hunted;
4: There is a redneck or two to make life difficult for the hunter;
5: There is a male protagonist seeking to thwart the hunter in his quest (for reasons unknown until the end); and
6: There is a major plot arc revolving around whether or not the existence of the creature should be revealed.

Not a carbon copy, though, as main characters die, including the creature.