I have been up to Mackinac Island only once, but I can't wait to go back! This place is so serene, peaceful, and safe. Everyone is so friendly and willing to help make your visit as stress-free as possible. It's a great place of a weekend getaway, vacation, or low cost honeymoon.
The best thing about Mackinac Island is that there are no gas powered vehicles allowed. No cars, motorcycles, or scooters. The method of travel on this island is strictly bike, horse drawl carriage, or walking. This makes it safe of little ones who like to run around and have fun. Just watch out for the piles of horse manure in the road! This is kept to a minimum though, it's not all over the place. You have to take a fairy ride over to the island from the mainland of Michigan. There are a few different companies to choose from, but they are all basically the same.
On the island, there are a few different activities you can pay to do. These include guided tours, carriage rides, and bike rentals. You can also hang around the island without spending a single cent! You do have to pay for the ride over, but once on the island you don't have to spend anything if you don't want. You can walk around the town, walk the path around the island, visit Fort Mackinac, and pack a lunch to eat on the beach.
If you do want to pay a little, I would suggest renting a bike and ride the whole trail around the island. It is a 8-mile beautiful trail along the beach. At some points you have bluffs on one side of you and the water on the other. Stop along the way and sit on the beach or get in the water. I sopped twice to get my legs in the water and cool off from the sun.
There are lots of little places to eat on the island, from cafés to fancy restaurants. We had lunch at one of the local cafés and it was good food for a great price. Mackinac is known for their fudge for a good reason...it's amazingly good! You can watch from a window or go inside one of the fudge shops to watch them make some from scratch. You even get to try a piece of freshly made fudge!
There are a few places to stay on the island, but they can be quite costly. We stayed in a campground on the water across from the island. It is much cheaper to find a hotel or campground on the main part of Michigan instead of on the island. If you don't mind paying a little more, go for the Victorian hotels on the island. They are beautiful! A family from the show "Extreme Makeover: Home Edition" was even sent to stay here on vacation while their house was being built!