Depends where you want to ride. You can park at the car pool lot on US-41 west of Ishpeming just west of Jubilee Foods. From there you can ride to trail 8 and head west to Michigamme, east to Negaunee/Marquette, west then north to Big Bay, or south to Sagola, etc.
You can park at the base of Marquette Mountain, near the ski hill, on County Road 553. If you leave town on 553 heading south towards the crossroads and Gwinn, it'll be on your left just before you finish rounding the curve to the ski hill. Trail 417 is right there. You can head east (by going up Mount Marquette, not the ski hill itself but the mountain) and head to Munising, or head west on trail towards downtown or to Negaunee, or hook up with trail 8 heading east to Gwinn.
I've seen a truck parked now and then at the welcome center in Harvey on lake superior, right on trail 417. Not sure if that's actually allowed as I don't see it too often.
You could probably check with the Objibwa Casino in Harvey and see about parking in their lot. They are right on trail 417 too, about 5 miles east of US-41 on M-28. Ride east on 417 to Munising.
You might even be fine parking in the parking lot at Lowe's (maybe buy something first or ask them) and heading north on trail 14 to Big Bay. The trail is just west of Lowe's parking lot (comes across US-41 there then heads up a big hill).
So lots of options.
BTW, how did your wife find NMU and you're still in MN?