The only decent xp is Chardok really. 1 Wing of HS is pretty good. Sebilis is garbage.
You're not going to find a good camp to totally afk in though. Someone will wipe your group, or report/fraps you.
If you just want to automate your group while you do other stuff at the computer, Chardok works well, specially the Dead Men Floating area etc. You won't be able to maximize a full groups potential because there's no area with easy automated pulling there, but that area has a good number of targets to kill every cycle.
If I catch you fully afk at any of my spots tho I'm going to wipe your group 8D.
Deleted a poor guy afk'ing Heirophant camp the other day. Automate all you want, but if you're not around to respond to tells/camp checks and you're at a high traffic area like Heirophant you're just asking to get banned/suspended. I've had Guides's check on me more than once already, but I'm always around to at least respond to them.