When you are trolling the Lake Huron shore line in the spring anywhere from Sanilac South to the river mouth, there is not much to focus on in the way of structure. It can be tuff unless you are one of the guys that gets out there very often. In my limited experience, i found that you need to focus on any little clues you can find. If you see seagulls diving, work the area. If the temp raises 2 degrees, work the area. When you come across a running creek mouth, work the area. There have been times when i've noticed a temp change and seen a fish swirl, and just kept on trolling because i didn't get a release...then regretted it an hour later.
The only real structure present is around LakePort State Park.
Sometimes when you get bad weather and wind there is nothing you can do.