Oh man. SWEET. I mean, I don't buy the individual volumes - since I get Shonen Jump monthly and buy the DVRAB, it kinda feels like overkill, ya know? - but getting far ahead in the serialization... good stuff. Thankfully I've been mostly familiar with the plot up to currentish, and re-affirmed the familiarity in preparation for the simulcasts. One Piece Wiki is a beautiful place.
While I do KINDA worry about people being lost... the real beauty of One Piece is in it's general simplicity. While, yes, knowing all the motivations and plotlines and characters is useful, a person can hop on at any time. You don't need to see Baroque Works to understand Skypeia, y'know? Luffy wants to find One Piece. Nami navigates. Usopp's a sissy. Zoro is awesome. There are certainly subtleties you'll miss out on, like the parallel between Luffy and Shanks during the Jaya Arc, or why the crew doesn't fully trust Robin, but the general gist is fairly clear.
Plus, they'll probably do the summaries, like they did with Naruto. So new readers will have a general idea. And, really, how many of us can say we started watching a show like One Piece from the VERY START. My first exposure was a few chapters of the Buggy Arc, then I started getting the serialized Shonen Jumps during Arlong. Naruto? I didn't really start reading/watching until the Chunin Exams. While context helps you understand a story to the fullest, with these types of stories, you don't honestly NEED it.
So, I'm betting they'll continue One Piece 'til the end of the Baroque Works Arc in Shonen Jump, then drop it for a few months and bring it back at Impel Down - which I know next to nothing about, so, yay a virgin read! I haven't had THAT since... ever, actually, with One Piece! And man, I was thinking a while ago that, at some point, Shonen Jump will be sending out issues with the last four chapters, fresh from Japan. Doesn't seem too far off.