museums in various cities

• South Bend
• Akron, OH
• Cleveland, OH
• Toledo, OH
• Pittsburgh
• Harrisburg, PA
• Philadelphia

portals

• World's Largest *, a list on Wikipedia
• RoadsideAmerica.com IN, OH, PA

specific things

• RV Hall of Fame — Elkhart, IN
• Hall of Heroes — Elkhart, IN

• Kent State Shooting memorial — Cleveland, OH outskirts
• Lego museum — Bellaire, Ohio (on the road to Columbus / Indianapolis, if we go that way)