One of the most absolutely stunning and beautiful areas of the US are the Springs of Central Florida. In the Orlando area, that would be Rock Spring at Kelly Park (best tubing), Blue Spring State Park (best swimming), Wekiwa State Park (best canoeing and hiking), Deleon Springs (historic grist mill and pancake house), and a bit further north in Ocalal National Forest there are Juniper Spring (most beautiful), Salt Spring (best snorkeling), Alexander (most natural) and others. They are tropical paradises, eye-popping beauties, each with unique features.
Even better is that the cost is about $5 per car, unlimited fun.
For most people the shock is that the water is cold. It is a constant 72 degrees year round, so it takes some getting used to. Some are so beautiful, and it is not practical to even get into the water.
I would say they are a natural highlight of the our country.
In addition, there are two other places to consider:
the Morse Museum of Art in Winter Park has the world's best collection of Tiffany glass, including installation pieces that were rescued form the Tiffany home in New York when it burned down. There is an entire Tiffany chapel as part of the museum.
The other place I will give a shout out to is Eatonville. Eatonville was the home of prominent African-American writer Zora Neale Hurston and was the first AA incorporated town in the US. It is a VERY humble place. There is a small visitors center with an exhibit, and there is a pamphlet with a walking tour. There is nothing sensational about Eatonville, but it is an important historic town right there in the Orlando area. To find it rewarding, you have to be open to exposing your kids to that kind of knowledge, which has nothign to do with thrills and chills.