Show Me The Way to Go Home
We were plagued with indecision in regard to choosing a route back to the Great Lakes.
If we go north on the Richelieu River we would de-mast Sea Star for the 9 Chambly canal locks, re-step the mast at Sorel (on the St. Lawrence Seaway), pass through the 6 locks south of Montreal and motor-sail against the strong current into the thousand islands.  We'd de-mast for the 2nd time at Trenton (Bay of Quinte, Lake Ontario) and motor through the 44 locks (240 miles) to Port Severn on Georgian Bay.  Once there we'd re-step the mast (for the 2nd time).
Our other option was to go back into the U.S. and sail south through Lake Champlain.  At the south end of the lake we'd de-mast Sea Star to motor through the 12 Champlain canal locks and the 33 Erie canal locks.  We have 2 options in regard to exiting the Erie canal; one at Oswego which would put us on the southeast end of Lake Ontario, the other at Buffalo which would put us on the southeast end of Lake Erie.
If we exit the canal at Oswego we are faced with either putting the mast up and down again or motoring across Lake Ontario to the Trent-Severn canal.
If we exit the canal at Buffalo we would re-step the mast and sail against the prevailing winds and current through Lake Erie to Lake Huron.

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As you can see, it wasn't an easy decision, but after great deliberation (no, I'm sure there wasn't a coin toss involved), we chose the southern route.  Our reasoning being concerns that Sea Star's aged engine may not withstand the (up to) 6 knot sustained, opposing current we'd face in the St. Lawrence Seaway.