Karnor's is used heavily as a leveling/AA zone and every single person that walks in cuts your profits per hour in half. If you can get the zone solo, its great, but unless you play at off hours, it isn't going to happen often. A duo at 45 might not work out that well anyway. You would be restricted to the front castle, you cannot single pull easily as higher level classes can, and a scryer spawn in the moat will be a rough end to the session. Not saying its not possible, just that you are basically running to nowhere hoping a very popular camp is open with no backup option in the zone.
RM Giants and OOT Cyclopses are the best money straight PP and sellables, since they have a merchant one island over. OoT gives xp til 51ish.
Level ~20 Kunark goblins in LoIO typically drop 2pp per kill and can be mass farmed in most cases with no competition.