Otter are almost like Mink with their territories in that they travel long distances and will return through an area every 10-14 days. I have caught two otters in my Beaver scent mounds in the last three years but had to turn both in because their is no season.
I caught them both at a state park 15 yards from each other and they stay there but that is because of the abundance of food but is not the norm. I would think the best way to catch Otters would be a good blind set that is a well travelled area. I have followed many a Mink in the snow and usually every Mink that comes through an area will travel the same path as every other Mink. I would believe Otters follow that same pattern.