For dungeons to go fast you need a healer of some kind, easiest way is go mages guild get scholar, promote to druid. Now it has AOE earth spell, single target heal and if more then one need healing the druid AOE heal is actually more mana efficient. Combine a seperate caster either MC can be one or another slave/peon and you got two mean AOEs, dungeons become easy. After that you just need some meat sheilds and i guess get an archer they got an AOE I beleive or was that sniper class, either way you will never have to hit next turn for hp again, and only have to worry about mana.
And since druids AOE doesn't use mana, and neither does the scholar fireshot or whatever its called. Really the one who runs out of mana the fastest is normally my MC who I go caster, and apprentince. Between the social spells and the ice aoe my mc is really only reason to stop fighting, minus when I clear a dungeon and have every one there strip out every resource before going to the next dungeon.
Oh and have you casters go theif as filler class especially mc so they can take turns opening things for more wit, wich seems to be the main stat for spell damage minus spell affinity. I never even paid back the 3k third week to date, doing dungeons and killing wolves gets me enough guild points I can start up the civil war and never have to pay a cent more of my mortgage once that starts. Between getting bandit leaders and random slaves from dungeons I give to the servants guild, and all the kill or run a dungeon/instance quests it happens pretty fast, and I end up with a pile of junk I don't want like 6 plate chests in no time, as well as other junk.
But if you must go the other way just do fishcakes, gather fish, buy grain make fishcakes sell, as you get more labor or cash get mats needed to grow your own grain, do that, and you got a super cheesy endless supply of cash