High Speed Feery from WI to Mi
We have ridden the ferry starting from both sides. Neither starting terminal has much of anything around it. The Milwaukee terminal had more food choices (although not many) than the Muskegon terminal, but the Muskegon terminal had some good homemade candies.
The snack bar on board is adequate. They grilled my hot turkey panini to order, and while not gourmet it was tasty.
If you are pressed for time, I wouldn't chance venturing too far afield. Even though the terminal is small and relaxed compared to an airport, there are still screening and boarding procedures. The Coast Guard has to follow homeland security requirements to allow you to enter the grounds, and if you have a vehicle it will have to be staged to be driven aboard. Not a big deal, especially compared to the hassle of airports, but you do not want to cut it too closely on time. The turn-around time on unloading/loading the vessel is very fast.
It's a very relaxing way to travel (assuming it's not a really windy day) - enjoy your trip!
Prior to getting on the ferry there's a small snack bar in the terminal as well. Not much more than chips and candy and both cold and hot drinks though.
If you have the transportation means, I might recommend picking up sandwiches or take out from somewhere downtown or the nearby Bay View neighborhood to take on the ferry with you. Keep in mind that the ferry terminal is an the industrial shipping area of Milwaukee and there's not a whole lot nearby (other than the excellent Three Brothers Serbian restaurant...but I'm not sure they're open at that time of day).
re: little debbie
You might consider going to the Milwaukee Public Market. It's just southeast of downtown Milwaukee, a little over a mile north of the ferry terminal. They have a lot of booths selling sandwiches and prepared foods and baked goods, perfect to take on your voyage. And it's always fun to see everything there - even if your visit has to be super-quick. www.milwaukeepublicmarket.org
Milwaukee Public Market
400 N Water St, Milwaukee, WI 53202