I'm storing at a place called Black's Storage right on MO 254 just west of the dam. On long weekends, I rent an overnight slip at Harbor Marina right by the dam. Storage is pretty reasonable- $50 a month and you get a free month if you pay for the whole year up front. That was for a 32' deep, with a 10' wide by 12' tall door. I needed the big door because of the ski arch, which is 11' 4" or something like that when on the trailer. You can get cheaper than that if you only need a 10X10 door. Lots of newer units down there now that 10X10 is standard, as well as 30' deep.
As for the crowds-tough to say. 2005 was the busiest Memorial Day I had ever seen on the lake. Last year-not so much. We chalked it up to fuel prices. So, I'm expecting a weekend more like last year. Lake is only up 3 feet, so that won't be a concern. Truman was up 16' last week, though!
Hoping the weather will cooperate. Give me a call if you come down.