The dress is officially business casual but many people wear jeans. I would steer clear of shorts (many of the rooms are cold) and open toed shoes (crowds + exposed toes = bad).
I stayed at Port Orleans Riverside last year and collected a lot of information. You can find a map of the property toward the bottom of this page: http://www.kingdom-travel.com/Walt_Disney_World_Resorts/Disney_Port_Orleans_Resort_Riverside.shtml
. You can pick up Disney shuttles all around Port Orleans. I think they run from about 7AM - 11PM and there is a bus stop off to the right of the main entrance (it's not on the map). They have a water shuttle but I never saw it and I don't know where it goes other than generically "Downtown Disney".
To the best of my recollection dinner is provided Monday and Wednesday nights, you're on your own for the rest of it. I think Tuesday night is the product showcase and hors d'oeuvre are provided.
You can get a Guest Pass for Lotusphere from Lotus Guest Services, which is beside the check in area for Lotusphere attendees. I believe that's in the Dolphin, but I honestly don't recall that specifically.