The joys of retirement!!
The only way I haven't done it is down the Mississipi... I've sailed the other ways: through Osweego or the Richelieu & Lake Champlain (down the Hudson to NY) but the better way for me is sailing to Gaspé then hang a right to the Magdalen Islands, Canso, Halifax, cross Fundy Bay to Bahaba... definitely a fantastic trip and you don't take the mast down!
The cost is of no real importance; time here is of the essence; the long way via Gaspé will take several months and you'll want to do the first legs in summer and you might even want to winter the boat along the way and make it a two season project.
This is no week-ending and some of these cruising grounds can be a little difficult (tides in the lower St-Lawrence, French in Quebec City, the whales in the Saguenay Fjord etc..)
If you wish some help in planning this don't hesitate, I've gone that way a dozen times now and know most of the nooks and crannies.
Of course before you leave the Great Lakes you will wish to take a last look at Makinak, the North Channel, Georgian Bay, western Erie, take in the sight at the top of the Welland canal etc. Pierre