Lovely boats, nicely overbuilt.... But you do realize the Michigan City to Chicago leg will probably be upwind in summer? And that the ComPac16 is one of the least weatherly boats on the planet? And slow? PHRF 318. OMG. You'll arrive in better shape than if you sailed a 420, but you'll take two to three times as long getting there. The Monty 17 is 40 points faster and just as solid.
Not to discourage the small boat idea -- I think it's brilliant.
I'd even advise keeping to the dinghy side of things -- not least because safe harbors can be hard to find along those lake shores, and weather can come up really really fast. It's nice to have a boat you can haul up onto any shore and wait out the ugly. So why not look for a small boat built for open ocean sailing but with a good turn of speed? The Mariner 19
and Wayfarer Dinghy
immediately come to mind. The Wayfarer would rate under 200 PHRF, yet people sail them all over the world -- including the Solent and Bay of Biscay. The Rebel
is an awesome piece of work. And while they are pricey, the Precision 15
is both faster and infinitely more stable than the Int'l 420. A 250# centerboard will do wonders.
We're totally behind you on this idea. Let's all pick our brains to find Gary the best boat available for what should be an epic journey! Tell you what -- when you find the boat, if it lacks a light air headsail, get me the particulars & I'll sew you up a nylon Code Zero that's easy to handle and will keep you moving in the mornings and evenings. My contribution to the effort.
ETA: Oooh, ooh, how about the Norseboat 17.5
? Tough as nails, carries lots of stuff, and you can land at villiages along the way to loot & pillage. Also it rows well.