I can recommend the “eastern” route South - (Oswego to) Erie Canals, Hudson River, outside to I.C.W & southwards ...
It’s a splendid tour, and a fairly easy route.
You’ve a particularly large boat, which will present a few minor (or not so?) challenges, no matter which inside route you take:
1. The canals have a 10 Ft bridge clearance. Can you clear 10' with the
mast lashed horizontally on/above
deck? There are facilities to de-mast at Oswego (& I presume Buffalo etc) and free materials to build your mast-storage “crutch”. Don't know about Chicago.
2. Boat handling in tight quarters can get interesting - but then you are an experienced power boater.
3.
Draft is always a problem /w larger boats. Over 6' gets problematic on the I.C.W.
I'd also reconsider a late season departure (which could be unwise on any route). If it's too late to go "outside", it may be (just plain) too late, period.
For what it's worth ...
Gord