Yeah that made me sad.
I was just commenting on how much I fricking LOVED Desmond. Dude was awesome.
Watched a couple episodes of Season 3 over the weekend (Further Instructions and Every Man For Himself). Michael Emerson plays Ben perfectly and for someone who isn't physically intimidating he sure puts fear into people.
IIRC, Michael Emerson was originally cast as a guest star, but did such a good job that they put him into the main cast as Ben. He's just a really great actor.
Also, on your island/boat question...I think that is explained fairly soon, but I don't remember. May defer to someone like OML since he remembers a lot more than I do about Lost.