Take a boat from MK to FW. When you exit the MK, the dock is straight ahead.
FW has cute pony rides and a petting zoo, but I doubt they are open after dark. Maybe you could hit them first. Don't worry about beast germs. They have a nice hand washing station and sanitizer there.
The campground also holds a nightly Chip & Dale campfire and sing-along. Look on Disney's website for the time since it changes with the seasons. I believe that there is also a horse and carriage ride between FW and WL.
The campfire is free unless you want to buy and make S'mores. You can bring your own chocolate, marshmallows and graham crackers. Or take out a home equity loan to buy them at FW's general store. (Just kidding.)
The pony and carriage rides are not free, but not too crazy priced (like the price of S'mores kits.)