I really think that you should try algonquin again, try kitten lake no portages, no motor boats, good fishing, close to access point also if you prefer there is a cabin there if the kids get a little tired! I wouldn't do masssasagua, there aren't any motor boats but it's on georgian bay which can get pretty rough, I've never been to massasagua but that is my feeling about it kids are just too young for it.