the ancient page quests at level 50 give something like 35m experience. so that will put you to almost 52. (note if you want, save these quests for later) the quests also give a good amount of gold, thanks to blessing marble, and blacksmith memo.

also.. joining demon tower climb's are not a bad idea.. the experience isnt the best.. but you have the chance to upgrade with better susccess. this is good if you want good items to metin2 yang at V2.

valcon 1 gives good experience, but these creatures poison.

black orc's give less and less experience, but some people prefer to train there till 55.

valcon2 is hard to solo till lvl 61, unless you have good ac AND 12k+ hp. but if you find a V2 party, these give the best experience. v2 passes can be bought from item mall for 180MP or from people ingame for 500k. (note - only buy from trusted people)

61-75

valcon2 would be a must here, i am not sure where else you would be able to train (unless you kill 75+ metins in WLF/DWLF) but thats mainly for money. lins demon keepstakle quest gives +60ac, which can help in metin2 yang lvl 61 +9 shield IS A MUST

metin2 yang can provide a nice amount of money/experience, i am currently lvl 59, and i make 5m xp an hour here. (45k xp a group of big spiders)

75+

dark wild leaf forest, or the kingdom of atlantea would be the prefered choice, as V2 gives less experience the higher you go.

metin2 yang  hunting in WLF/DWLF gives a very good amount of gold.