Hooray for you!! Diving all 5 Great Lakes is a cool thing to do. I agree with all of the above posts too especially that Tobermory is not to be missed.
Lake Erie: we dove with Osprey Charters out of Westfield, NY.
Lake Michigan west: lots of great dives out of Milwaukee. Ive always found Milwaukee diving to be easy and relaxed the rides out to the dive sites are not long, and the dive groups tend to be pleasant and easy-going folks. Our two favorite captains are Captain Jerry Guyer from Len-Der Charters.
www.len-der.com and Captain Dan Johnson from Loves Park Scuba (Illinois).
www.lovesparkscuba.com Captain Dan takes his boat to Lake Superior and northern Lake Michigan as well, so you may be able to dive several locations with him. Out of Chicago, there is the Divers Dream Dive Boat (they have a facebook page with lots of information).
Lake Michigan east: Traverse City Dive Group (Facebook Group) has quite a bit of information on local shops and dives in the Grand Traverse Bay Underwater Preserve.
Lake Superior: Weve only ever gone to Munising, although Ive heard great things about the other spots. Out of Munising, there are a couple of very shallow 20 range wrecks as well as wrecks in the 60 and 100 ranges. Since some of these wrecks are in more sheltered waters, weather is not quite as much a factor as it is in other spots (which isnt saying much). There are a couple of charters out of Munising. We dove with Captains Linda and Randy from North Star Charters:
North Star Charters - Pure Michigan Travel
Lake Ontario: Eric Cooper runs Aquaholics Underwater out of Grimsby, Ontario.
www.aquaholic.ca and he has a facebook group as well. Kingston is on my bucket list, but until then, Grimsbys not a long drive for us.
Lake Huron: Tobermory, of course.
Alpena is terrific.
Welcome To Great Lakes Divers
Port Sanilac is our home base for Great Lakes diving. Brunos Dive Shop.
Bruno's Scuba and Hockey Shop. Gary Venet
Rec and Tec Scuba Dive Charters - Lexington Michigan, Thumb area Preserve, Sanilac Preserve Four Fathoms Diving
Four Fathoms. Scuba Equipment, Training, Michigan Wreck Diving.
A Great Lakes tour is a wonderful idea! The only comment I have is that it will take patience in all of our diving, weve had many charters cancelled due to weather.
Have fun!!
ps - All my Great Lakes dives have been wetsuit diving (and in an old beat-up wetsuit, at that). It is cold, but gives you street cred. Or so I'd like to think....