40 - 50, you go to Kerning Square, no need to do the quest, just go up to CD's, that'll be where you're going to train until 50. Classes who can rush monsters in 2nd job is going to be faster to level here, you just keep rushing back and forth, which isn't hard at all haha, just gotta hold 1 button and rush. Mechanics are the best IMO to train at CD's from 40-50, got quite a few Mechanic Arm's there.
Cds
Lvl 41
Exp: 99
Cds2
Lvl 42
Exp: 101
Once your level 50 you can go to drakes in sleepywood untill 55.
Drake
Lvl: 51
Exp: 141
56 - 60 - Trojans
Trojans - Great spawn, not such a big map, fast exp, not much to say, but have fun training!
Trojan
Lvl: 57
Exp: 172
60-65 robos or 70.
Red / Blue Robots - Robots, the red / blue robots. The map where I went to (Had both of the robots) was amazing. Easy to train, platforms are small, but amazing spawn. I guess you could say it's like the Zombie Mini Dungeon in GMS, the bottom has the most spawn. There are exactly the same amount of platforms.
Robos
Level:60 and 62
Exp 204 and 222
65 - 70 - Puppets / Zeta Grey
Zeta Greys (The Omega Sector monsters) or Puppets - Well, like any other I've said. Great spawn, and fast exp.