Looking at site recaps, I can confirm the following. Going from west to east:
*All 13 Western states (MT/WY/CO/NM and westward)
*South Dakota (Mount Rushmore)
*Texas (several destinations)
*Minnesota (Mall of America)
*Missouri (St. Louis, last time offered on Bob's 90th Birthday, and in 2004 before that)
*Louisiana (New Orleans)
*Wisconsin (The Dells)
*Illinois (Chicago)
*Tennessee (Nashville, Memphis)
*Michigan (Mackinac Island)
*Indiana (Indianapolis)
*Alabama (Huntsville Space Camp)
*Ohio (Cleveland)
*West Virginia (Lansing via Charleston)
*Georgia (several locations)
*Florida (many locations)
*New York (several locations)
*Pennsylvania (Hershey, I'd wish they'd offer Pittsburgh/Philadelphia since they are decent places to visit
*New Jersey (Atlantic City)
*Maryland (Annapolis)
*Washington, DC
*Virginia (Hot Springs via Roanoake, Williamsburg may have been offered a long time ago)
*North Carolina (Ashville)
*South Carolina (Hilton Head/Charleston/Myrtle Beach)
*Vermont
*Massachusetts
*Rhode Island (Providence)
*New Hampshire
*Maine
As for the states that haven't been offered to my knowledge:
-North Dakota/Kasnas simply doesn't have much to offer being flat and boring.
-Oklahoma has some hilly sections in the east, but I'd have Hot Springs, Arkansas if offered cover that
-Iowa is close to the Wisconsin Dells in the East, but like Kansas/N. Dakota is another state without a huge tourist draw.
-I could see Arkansas being offered due to Hot Springs and the Ozarks.
-The Kentucky Derby makes Louisville a decent destination, though since NBC runs that event, it doesn't seem likely.
-Mississippi does have a coastal section (Biloxi-Gulfport), but much of that could be done with an easy day trip from New Orleans, and if Memphis is offered, that can cover the northern part of the state.
-Did you know that currently Delaware is the only state with no commercial air service? That means that Philadelphia or Baltimore are the closest airports to reach it, which is a huge red flag for any chance of a trip to this state. There is NASCAR and a big music festival in Dover in June along with some beaches, but overall this state has quite an under the radar feel mostly because of its small size.
*Connecticut does have some beaches and some quaint towns, but they tend to be more working as opposed to tourist-oriented, and lacks some of the big hills/mountains to states further North/West. Providence could cover the Mystic area for a day trip, and for the western portion, just take a Metro North train if you happen to win a NYC trip.
So, thats 41 states plus DC that the show has offered, and its unlikely that all of the other nine would be offered. Of them, I would most like to go to Mississippi.