Did you fully do the goblin camp? After that you should/could already be level 5, if you didn't skip any content. My personal order is Goblin Camp, Auntie and her minions, Mountain Pass Creche, Mountain Pass Undead Shepards, Underdark. Auntie is easily doable at Level 4 even on tactician. The undead encounter is also not very difficult, they are annoying for sure but using cc and aoe spells and having a cleric and maybe a paladin in the party is the way to go here. The Duergar in the Underdark are only difficult if you enter the decrepit village from below and not above (coming from the spore colony), you need to Obi Wan this fight.
