Maybe this is neighborhood specific, but most of the SFH within a few square miles of me sell with ADU price per square foot the same as the main house.

In case you haven’t read the previous responses or haven’t walked a mile in a landlord’s shoes. 90%+ of your problems are caused by your local/state government that you seem to be giving a free pass.

For example, I have rentals on both north side and south side.

Live in Northern Va, but looking at eastern North Carolina markets.

To improve your business going forward, it is important that you recognize how you created the problem.There are a portion of residents that if you give them an inch, they will take mile. 

I keep hopping around from Florida to Nashville to North Carolina, maybe Ohio for the lower price point when I was considering buying more than arbitrage.  

For example North Carolina is $40,000 or less, Texas there is no limit, and so on.

We don't own any properties in Sheboygan, the furthest north is Port Washington and that has been great.

What would you say is the average occupancy and daily rate for a 1500 SF 3 bedroom home in good condition around a mile from the beach / pier? 

They are not buying in cities 1,000 miles away from where they live.