The shuttle runs weekends from mid-May to mid-October. It's best to leave your car, ride the shuttle, and hike back to your car.
Earlier in the year is better for water in the small streams but you'll come to a good water source a few times each day.
I live in Finland and that has some nice sections of trail but anything south of Grand Marais is beautiful.
And yes there are bears on the trail, I've seen them. Hang your food away from camp and you shouldn't have a problem though.