An Easy achievement to get in all honesty. You begin by getting off the boat to get gas. Just play through with friends, random people, or by yourself. Although just because bots generally aren't the best, friends are suggested.
You'll eventually get to the mill which has a large number of witches. Stay away from then when possible. If they are in a tight section of the map, you still have a decent chance on being able to run right past the witch. Just don't make eye contact and have your lights off.
Be careful for what ever is in the corn field. When you get to the safehouse, get the gas, and come back out there will be a storm coming. The storm causes 'puddles' of water to form all over the place which will slow you down significantly. In the corn field it's a good idea to hop up onto the pipe to run across.
This storm will cause the area to flood quite a bit. Which results in hard and slow navigation. Every now and then the storm will pick up, hard, (hence the name) and your view will be extremely reduced as well as your ability to hear due to thunder and rain. Just watch out for a horde or two and try to keep close to your allies. A jockey hopping on someone here could be an issue if you are too far away to get it off.
You just keep backtracking until the end, start the final fight and hold your ground as best you can. Then get on the boat and have fun.