The upper Croix and lower Croix (Taylors falls south) are pretty different stretches of river, and there is 169miles between source and mouth. The Upper river is for the most part, fast and shallow, while the lower river has some hoes that are close to 100′ deep.
Having fished the upper quite a bit, it’s not too hard to find them. Find a deeper hole (15′ or deeper) and anchor on the upstream edge of the the hole and you will contact fish. Pretty much anywhere you fish, you have have a chance, but holes tend to harbor bigger fish.