I really suggest doing 4-1 for a while. The end boss there is pretty easy and so is the 4-2 one.
Be VERY, VERY careful of you world tendency. If you go towards Black, you're screwed early on.
Also, don't feel bad, Flamelurker is one of the hardest bosses in the game, right along King Allant.
Farm 4-1, 4-2, it's about the best place at lower levels. They're not easy, make no mistake, but very rewarding. Also, 1-2 is pretty decent in that regard and you can get a decent boost by killing the bridge dragon.