Black flies can be bad in spring and mosquitoes take over in early summer, so bring insect repellent. In spring and early fall, be prepared for frost. Fast enough to make miles, light enough to portage, deep enough to safely take waves, and large enough to carry packs and two or three people. Best are streamlined canoes at least 18 feet long and made of the strong, lightweight material called Kevlar. Slightly shorter and narrower canoes, with a seat amidships, are good for solo paddling.
Sea kayaks are great for large lakes, but they're tough to portage between lakes.
A Duluth pack is traditional. Pack sleeping bags, food and warm clothes in waterproof, roll-top bags. It's perfectly all right to break up downed wood for a campfire, but a gas stove saves the day during rainy weather when a wood fire is hard to start. You'll also need a stove if fire danger is high and campfires are restricted. You'll need to be prepared for heat, cold, and rain.