You are in the wrong forum but I can still help you a little.
You have to walk to Kerplunk. Make sure before you do anything that you sign the coach ledger. It's tough to get to kerplunk at your level, lots of mobs, you'll need inviz and watch out because some of the casters can see inviz.
The raiders you need to kill are on a hill not far from the village of Kerplunk. There are treants that will kill you if you get too close. I recommend getting someone much higher level to come with you so they can kill off raider for you. That would make it easier to get to Kerplunk too.
That quest has been a problem since beta for frontiers.