Tip 1: In the earlier missions, send your lord towards Wintertop and use him to clear out the estate. In mission 4 a message will appear at the start saying Wintertop is free of wolfs.
Tip 2: Outlaws can be an extreme pain, however there is a way to deal with them, make two groups of around ten archers, one to boorswell near the marsh and one near Sir Grey's estate that is wrecked due to the outlaws. The outlaws should not be able to make it to your castle if done corectly.
Tip 3: Slow those outlaws down! Make some Armed Pesant's and waste there spears plus weaken the outlaws.