To add to some things by GLSC and RnRHOF. There is the USS cod submarine and the Steamship Mather which the last I knew are on the 9th street pier next to GLSC. Also I think the Goodtime 3 departs from that pier and tours Cleveland via the Lake and into the old Flats area.
US Cod
http://www.usscod.org/#_=_
The steamship I think is part of the GLSC
Goodtime 3
https://goodtimeiii.com/site/
Federal Reserve Museum and Tour
https://www.clevelandfed.org/learnin...it-us.aspx#_=_
Churches
http://www.ststanislaus.org/#_=_ Renovated and restored to its original status, repaired after fire
http://sttheodosius.org/#_=_
http://saintjohncathedral.com/#_=_
Farther south is Bath, OH is Hale Farm and village-a working reconstructed 19th century village.
http://www.wrhs.org/plan-your-visit/hale-farm/#_=_
The Cuyahoga Valley Scenic Railway: Think it departs from Independence, OH running south
http://www.cvsr.com/#_=_
Oh and if you like Corned Beef and are near the Cleveland Clinic area stop at Vienna Distributing Co of Ohio (8110 Carneige) There is no place to sit (mainly just a deli case) and I don't think they make sandwiches for you but you can buy hot fresh sliced corned beef and a loaf of rye. (They sell mustard by the jar but I don't bother since it all gets eaten before I have a chance to spread it) Whenever I visit Cleveland I try to stop there. I wish my mother in law would drive into the city to get a few pounds before her visit-might even invite her then