See if you want my opinion, i would say that :
If you are lvl 187 and you want to lvl up fast, then there's no map that you can lvl fast, you must lvl slow. Go to Oro and you will find some Golems , hunt them you will get some good EXP. But when you will go to lvl 195 it will be hard for you to lvl there as the Exp will be less than 1 each monester. So you must go to Underground prison from 195 to 200.