I sailed from Milwaukee to White Lake, then to Pentwater and then back to Milwaukee on a Precision 23. We motored over due to lack of wind, and had a great sail (2-3 foot waves during the day, and 4-5 at night) on the way back. We covered about 70 miles on the return trip. In any case, the optimal size of the boat depends on a lot of factors including the captain/crew and just as important, your schedule. The C22 can certainly handle a lot of rough weather but it may not be comfortable. I would take my O'Day 222 across if I had the right weather window, but I wouldn't want to be in a situation where I had to go on a day when the weather was deteriorating significantly. It's not that I don't think I could handle a lot of situations (I have roller furling on the jib, and two reef points in the main and the boat is setup well for coastal cruising), it's just that it would be uncomfortable at best and you are pushing the envelope a bit if things really get bad. In my opinion, if you want to do this quite frequently, then something in the 25 foot range or bigger would be better (e.g., Catalina 25, O'Day 25 or 26, Seaward 25, etc.). But there is a tradeoff. Launching, retrieving and towing is more of a hassle unless you are on Michigan a lot. If you are flexible on when you cross (both ways), you may want to consider going across with your current boat assuming it is properly equipped. I'm probably going to do that next year with my O'Day. Or, just charter one and go across. Just my two cents.