Every state has multiple cities and in many cases, if you've seen one you've seen them all. But there is only one Grand Canyon, one Everglades, one Yellowstone, one Death Valley etc etc. I am currently on vacation in Florida (visiting my wife's father). I am near Clearwater but am taking in the natural attractions such as snorkeling with the manatees in Crystal River, visiting Homosassa Springs State Park, etc.
Look for the natural wonders or unique experiences that are found nowhere else.
For example, rather than staying in Miami, you could drive down the Florida Keys to Key West. You could even take the ferry 70 miles out to sea and visit DRY TORTUGAS NATIONAL PARK for the day.
When you are in the Orlando area, check if there are any rocket launches at Cape Kennedy. Not a natural wonder, but a unique experience.
When you get home and share your vacation experiences with others who have visited the states, they will be surprised at what they had missed.