Battleship Memorial Park
We discovered Battleship Memorial Park, home of the USS Alabama, by accident: We were driving along I-10, traveling from the Naval Aviation Museum to Stennis Space Center, when we saw a gigantic warship out our van window. With a little bit of investigation, we found out what we had missed and added it to our list of places to visit "next time."
Battleship Memorial Park is actually two destinations in one: A $2 parking fee gains admission to the park itself, which includes access to their B-52, C-47, collection of tanks and artillery, whatever aircraft or missiles might be parked outside (during one visit, their A-12 Oxcart was parked outside, and on another their Redstone missile was outdoors), and "outside the fence" views of the battleship USS Alabama, the WW-II Gato-class submarine USS Drum, and B-25.
Paying $12 a person then gets you inside the fence, which also gives you access to the Aircraft Pavilion. While primarily filled with more modern planes, the Pavilion includes the A-12, a rare Kingfisher seaplane, and a P-51 Mustang.
With your admission ticket, you get instructions for three separate self-guided tours of the Alabama. You can choose to follow the guide or go off and explore the battleship on your own. There are very few places on the ship which are chained off or protected with Plexiglas barriers. They've even cut access doors in a 16" gun turret's barbet (the armored "socket" in which the main turret rests) so you can see the turret's interior. All three 16" gun turrets are accessible from the deck, as are several of the smaller gun turrets. And some of the anti-aircraft emplacements on the upper levels of the ship still rotate when you turn the crank (the ones on the lower levels do not -- perhaps they thought that any urge to turn the turret's crank would have worn off by the time you climbed that far?).
And, as if that weren't enough to fill your day, you also get similar access (although no tour sheet) to the USS Drum. The similar USS Cobia at the Wisconsin Maritime Museum limits you to a relatively short guided tour, with most places off-limits. On the Drum, you can actually climb into the conning tower if you like!
Although I'm primarily an aerospace guy, I have to say that exploring these two warships was a great experience!
Google Maps link.