Sounds like you've got a pretty full schedule for one full day and 2 half days!
Okay, so we went last year, and we rode the giant ferris wheel on the Boardwalk. But, overall, I felt that the boardwalk was a bit trashy, and very overrated. But, the ferris wheel was fun. Also, there is a ton of mini-golf.
There was actually an indoor outdoor shopping/entertainment place about 0.5 mile inland from our beach hotel (we stayed at Caribbean Resort). I felt it was VERY reminiscent of Downtown Disney, and we were really pleased with the amount of things to do there! There was a theater, lots of specialty souvenir shops, a boardwalk (different from the "strip" boardwalk with the ferris wheel), and just different fun places to eat, etc. Worth checking out, in my opinion.
Mostly, we just enjoyed our resort (and it was truly awesome) but I wasn't overall impressed with MB. We would go back again, though, because the resort was so awesome!