To me, this is one of the most underappreciated attractions at Disney. I must admit to being partial to Twain's "The Adventures of Tom Sawyer" and enjoying the tie-ins (like the caves), but it is beautiful for so many other reasons too: the view of BTMRR from the bridge to the fort, the fort itself (I'm bringing my harmonica for the rocking chair next time), and, most beautifully, the splendor as a majestic steamship comes by.
Twain's autobiographical "Life on the Mississippi" really captures it best:
"all go hurrying from many quarters to a common center, the wharf. Assembled there, the people fasten their eyes upon the coming boat as upon a wonder they are seeing for the first time. And the boat is rather a handsome sight, too. She is long and sharp and trim and pretty; she has two tall, fancy-topped chimneys, with a gilded device of some kind swung between them; a fanciful pilothouse, all glass and “gingerbread”, perched on top of the “texas” deck behind them; the paddle-boxes are gorgeous with a picture or with gilded rays above the boat’s name; the boiler deck, the hurricane deck, and the texas deck are fenced and ornamented with clean white railings; there is a flag gallantly flying from the jack-staff; the furnace doors are open and the fires glaring bravely; the upper decks are black with passengers; the captain stands by the big bell, calm, imposing, the envy of all; great volumes of the blackest smoke are rolling and tumbling out of the chimneys – a husbanded grandeur created with a bit of pitch pine just before arriving at a town; the crew are grouped on the forecastle; the broad stage is run far out over the port bow, and an envied deck hand stands picturesquely on the end of it with a coil of rope in his hand; the pent steam is screaming through the gauge cocks; the captain lifts his hand, a bell rings, the wheels stop; then they turn, back, churning the water to foam, and the steamer is at rest. Then such a scramble as there is to get aboard, and to get ashore, and to take in freight and to discharge freight, all at one and the same time; and such a yelling and cursing as the mates facilitate it all with! Ten minutes later the steamer is under way again, with no flag on the jack-staff and no black smoke issuing from the chimneys. After ten more minutes the town is dead again, and the town drunkard asleep by the skids once more."
I can just hear that paddlewheel turning....
You are so right about the rain! I have to tell you all a secret! You can't tell our kids! 
On our adult only trip a few months ago (I keep saying a few months ago so it doesn't seem like its been too long since I've been there) it rained all day at Epcot. It seemed like all day anyway, but after awhile, I just "went" with it and started splashing in the rain puddles. I was watering my Keens so I didn't have to worry about getting my shoes wet and had so much fun kicking and splashing the water! I felt one a little kid again. My DH was laughing at me but it wasn't long that he was doing it too! It is one of my favorite memories of that trip!
Fortunately for most part, they are quite quick. One particuliar rainfall I recall is when we were in Downtown Disney on 8/31/07! We ended staying in the World of 
)
Five family trips to WDW and my kids have yet to see the inside of those caves!
I love your pictures!
