Sadly there won't be any NA Beta in the near future...
Right now B&S is in CB2, and Ncsoft has stated they wanted to have at least 5 betas and then Open Beta. So B&S probably won't be coming out till at least Q2 2012 in Korea, and who knows how long the west will get a release.
The Open game world is extremely small atm, but with every CB event they seem to be adding more zones. But there are instance dungeons all over the place.