How to win with a “weak” Knight?

Are you referring to a chain of heroes for the Knight on Good and Evil? It takes a long time to do, and it might end badly, as beavers are running around nearby. I wouldn't risk it; just have the main hero and a hero-squire to improve turns and maybe for the joined units. Although, of course, I've changed my tactics a bit to be more aggressive lately. As for the sawmill, capturing it still seems less worthwhile compared to getting 2 stacks of boars and 3 stacks of orcs for free.