Bed and Breakfast or Hotel/Motel in town. There are lots of options!
Goderich does have rules regarding these types of accommodations, but they do still exist. If you’d like to book an entire house for yourselves, you’ll have lots of luck just outside of town in the cottage communities around the area. Many of the rental cottages have awesome lakeside locations!
Keep in mind you'll have to drive to get to Goderich