Haunted House
Visit the "Haunted House: Chimney Possessed by the Scarecrow" when you are at levels 50 to 55 and fight the dead scarecrows. The chimney possessed by the scarecrows is located in the Prendergast Mansion. It is inside the mansion's main chimney on the right side of the mansion map, and the scarecrows are in the middle of the chimney. Prendergast Mansion is located in Phantom Forest. Dead scarecrows are level 50 monsters with 3,300 hit points each. Killing one will give you 220 experience points.
Swamp
Two more training spots to go to while you are at levels 50 to 55 are the Silent Swamp and the Humid Swamp in Sleepywood, where you will encounter copper drakes. A copper drake has 3,000 hit points and killing one gets you 130 experience points.
Zipangu
When you reach level 55 go to Zipangu: Vanished Village to fight water goblins and samiho. Water goblins are green kappa, which are humanoid monsters with beaks for mouths. Each one has 5,500 hit points and gives you 194 experience points. Samiho are three-tailed foxes with 6,300 hit points and give you 213 experience points each.
Malaysia
To train during levels 60 to 62 head to Malaysia: Muddy Banks 2, where you will encounter rodeos, strange-looking hippopotamus monsters with small pink riders. Rodeos have 5,900 hit points and give you 226 experience points. For levels 63 to 65 go to Malaysia: Muddy Banks 3, where you will find a monster called a charmer. It is a snake charmer with a flute, and it has a snake coming from a basket on its back. Each charmer has 7,500 hit points and killing one will give you 269 experience points.
Prendergast Mansion
For levels 65 to 70, return to Prendergast Mansion in Phantom Forest. Once you get there head to Haunted House: Chimney Possessed by the Clown to encounter the Twisted Jester. The Twisted Jester has 50,000 hit points and gives you 1,325 experience points for killing it.