Sacred Haven of Debauchery

I'm trying to beat the Lord of Destruction campaign on impossible difficulty for the second time. The first time, I played as a Warrior (I've already beaten the campaign as a Paladin on medium difficulty, and as a Mage on hard), but it didn't quite work out. Now I'm playing as a Paladin again. It's already the twentieth game day, and I'm still with the Dwarves. I have to run away from all enemies except those who are "slightly stronger," as they fight almost or completely without losses. And yet, about 80% of the units are very strong or deadly. At least, gold isn't as scarce as it was when I played as a Warrior.