From what I have read, it seems that if you are staying at an on-site hotel, walking really is the simplest and most straightforward method of getting to the parks. The shuttle means waiting, and still includes walking when they drop you off. Same for the ferry - you have to wait, and then walk from CW.
So if we have five in-shape and able-bodied people in our group, is walking the way to go? Or am I missing something?