There are suprizingly more drains in the car than you think. Some have amazing routes they follow. It may be difficult to get in a good waxing of the car depending on the temperature when you store it. High quality wax will be too difficult to put on when it's very cold. But, you may luck out and get this done.
Brake dust is very corrosive.
You do not want this sitting on your wheels for the winter. Remove the wheels from the car. Clean the outside and the inside. The cleaning process is slightly different depending on the type of wheel you have. Some amount of wheel cleaner such as P21-S may be needed to get the insides really clean.