PoJ zone out was always great till about 55-56.
I spent most of my time from 56-60 in PoD cy, but not sure that you could solo it.
Before the Planes came out I knew a lot of people who got to 60 on the plateau in Scarlet Desert. I believe that zone is listed as a hot zone right now as well, so the exp there might be pretty good.
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Some people are like slinkies, they aren't really good for anything, but they still bring a smile to your face when you push them down the stairs.