I love places like that too - it was a trip funded by my college as a New Student Experience program - I meet new people, do this trip, and earn 3 credits for college all for under $550. Anyone going to SU, I highly recommend doing it.
Well once I get to NG+, it doesn't matter how many +s you have - anyone from any playthrough after the first can join. Just not the first :P it's really just a matter of going into NG+ and getting to Iron Keep.
...Actually I haven't played Dark Souls II since the day we tried :| I've been playing Reach, Skyrim for the first time in forever, and attempting to finish the Games with Gold I got. I could try running through it really quick if you want.