Well, I'm level 27 and I'm just up to Haas' Labyrinth (for the second time

) so level 24 is a bit low. Have you cleaned out the land of dead, and things like all the pirate ships in the Freedom Isles?
I think you have fallen into the trap of just going up and whacking the enemy. Even as a Warrior, this is not recommended. You need to bait the enemy more with cannon fodder/summoned troops.
As a counterexample, I am playing as a Hard Mage for my second game, and I have about 900,000 gold now.

But I still have to kill the 7 manifestations of Haas.
My only suggestion: if you get yourself killed King Mark gives you money to rebuild your forces and a really lame stack. Is there anything stopping you from deliberately letting yourself die several times (without buying anything) to make enough cash to get going again? Anyone tried this?