Knock on wood we've had very good luck with our course in Southern MI. We applied for a permit and dropped it in the lake about 13 years ago. We only had to apply for the permit for three years and then we were basically grandfathered in.
We purchased an insta-slalom course and started with 8' buoy lines. Our concern was about keeping the mainline lower along with the pvc. We found quickly that it was actually better for folks (non skiers) to see the mainline and the PVC booms so we revised all the buoy lines to 5' long. This also helped the course float better. Some folks were clueless at first. They'd anchor through it, get their anchor caught on the mainline, or go tubing through it.....
The first year we had some issues with a few fisherman and locals but the best advice I can give you is to kill everyone with kindness. Many people will respond much better when approached with a smile. Even this past weekend we had a fisherman fishing in the course. We didn't do a drive by and spray him........ :-P We pulled up slow, said hello, asked him how they were biting and simply asked if he minded if we took a rip through the course. He said "sure no problem, I enjoy watching you guys." A few weeks ago we had another that asked if he could stay in that spot for about 10 more minutes as the catching was good. We said no problem and about 10 to 15 minutes later he moved out.
There's always been this terrible wall between skiers and fisherman. We do end up dealing with a few grouches but my best advice would be to mend the fences between the two groups on your public lake. Be kind. If you get a grouch who won't move then go for a good free ski. Non of us our pros on our lake so it's easier to ski the course another day and not have a group of folks building a resistance against skiers.
In the past 13 years we've had the sheriff called on a ski boat once because a fisherman said skiing wasn't allowed when people were fishing.....
Oh, lastly. Our course sits in water that is 30' to 75' deep. We have one spot in the middle where it's about 10 feet. We have actually never pulled the course out. In October we pop all the balls off and let it sink to the bottom. One of my close friends is a diver so in the spring he dives down and floats each section up. The mainline is in great shape for being the water that entire time. The pvc has some algae on it but that's about it. Good luck!!!!