Hey Dodo
If i remember right you're an SK
For level 50+ I like the plane of power zones just because they're easy to get to and the next level bracket is close.
50-55 Plane of innovation stuff is singles or doubles, they are social but its pretty easy
55-62 crypt of decay again singles or doubles
62-70 Plane of fire first castle you can lev into from high on the wall, first castle is social but everything that isnt in the huts will come single agro range is pretty low, once you're higher in the range you go to C2 it's the same deal.