Best place for solo farming?

First let me be clear. I know Im doing multiple posts all of them close in time, my intention is not spamming but being clear. I also believe info that i get from posible answer will be more searchable if the topic says it all.

To the point. I find myself sometimes farming alone. Obviously you cant always find a party to go ao2:5, and you cant go there all by yourself. So if i was going to farm some cash, where would you say is better if Im on my own? Same for items.

PS: Im lvl 45 but not on pinks...

solo farming is easiest on stage 1. run up to boss, kill, repeat.
it's also easy in 2, although you have the mummies to kill(not hard) and lesser djinns.
level 3 is similar to level 2, but a slight harder.
level 4 is near impossible,
level 5 is impossible,
plasma is doable with trashcan punch

if you are an elf or avian you will have trouble.