The states I have been to ...

Florida: Major cities - Gainesville, Orlando, Daytona, Tampa, Sarasota, Clearwater, Miami, Key West,Jacksonville etc.
Georgia: Major Cities - Atlanta, Athens.
North Carolina: Smokey Mountain National Park.
Tennessee: Smoky Mountain National Park.Major cities - Nashville, Knoxville, Maryville, Gatlinburg, Chattanooga.
Kentucky: Drive through
Illinois: Major cities - Chicago, Urbana-Champaign, Places around Fermilab in southwest suburb ( Naperville, Aurora, Batavia)
Indiana: Drive through
Ohio: Cuyahoga National Park.Major cities - Columbus, Cleaveland, Akron.
Wisconsin: Drive through
Minnesota: Major cities - Minneapolis, St.Paul, Mankato
California: Major cities - Los Angeles, Riverside, Monetery, San Francisco. (Drive through Pacific Coast Highway)
Arizona: Grand Canyon National Park.
Nevada: Major cities - Las Vegas.
Massachusetts: Major cities - Boston, Amherst.
New Hampshire: Kankamagus Byway. Major cities - North Conway
Vermont: Major cities - St.Johnsbury, Bennington, Brattleboro.
Delaware: Major cities - Wilmington.
New York: Major cities - New York, Buffalo/Niagara Falls.
New Jersey: Drive through.
Washington D.C
Virginia: Drive through.
Maryland: Was born! Drive though.
Pennsylvania: Major cities - Pittsburgh.
West Virgina: Drive through

Makes it 24/48 mainland states until now, with a defintely a few more coming up before the end of the summer.