Just wondering if there's a group of people that would be interested in knocking out achievements? Many can be done solo but there are dungeons that require at least 3 (Crade of Decay)-4 (Black Castle) people and of course the 6 man dungeons. I think the easiest thing to do would be to go in order. We could also find various wide hunting grounds to knock out hordes of vanir, hyperboreans, bugs, prey, acheronians, undead, etc. If we're in a group and in the vicinity (aka 'red'), everyone's kills count - I've tested this already. We can also set up lookouts at the various rare boss spawn points, kill placeholders, and announce when we see one spawn so group can kill it as a whole. I know where they all are because my map tells me.
Let me know if you're interested and when you'd be available so I can try to set up a team or raid as well as a regular achievements time! :)