I can relate to it. The feeling of being so far from the current episodes of an anime. Pretty much the reason why I didn't watch the entirety of detective conan episodes. It has even more episodes than One Piece, haha. I think I've only seen the first 100 episodes. But yeah, I do plan to watch it the first time I get my hands on my PC. I haven't had the chance to touch my PC in six months since I resigned so I don't really watch much anime these days.
Jo...idk, she was around 360 episode mark last I asked her. But she's being a little slow now. Mostly due to life being busy and X/Y games. D; Either way, if the show is good, I think you'll have problems. Don't think of catching up - just watch one-two episode per day and enjoy watching to its fullest. Plus, it is more fun to marathon series anyway than to wait for new episodes each week. Also, if you don't want to watch too many episodes JUST to decide whether or not you'd like One Piece, I'd suggest trying this one OVA. I'll link it to you.