Can you go by boat from Old Hickory Lake TN to Lake Erie and if so how?

Yes, you simply lock thru Old Hickory Dam, Cheatam Dam, and Barkley dam (all part of the Cumberland River). 30 miles after Barkley is the Ohio River which carries you to the Great Lakes. See the following link. This is part of the Great Circle around the entire eastern half of the United States.

Albin Trawler - "The Great Circle Waterway" ICW