I have heard the comment before about there being no place on the Great Lakes that can handle that large of a group and don't understand where that belief is coming from. There are a number of cities with facilities that should be sufficient: Toronto ONT, Rochester NY, Buffalo NY, Niagara Falls NY (maybe), Hamilton ONT (maybe), Cleveland OH, Toledo OH (maybe), Sault Ste. Marie ONT (probably the smallest town in this list, but it can handle that size group), Chicago IL, and Milwaukee WI. I have also heard, but have been unable to verify it myself, that Traverse City MI has sufficient facilities.