Personally i had an external map in the beginning but now i find myself being able to remember where everything is and i think it helped me to get a better view and path of the map. both me and my friend work well now even without an external map.
Hey me and a friend are looking for a third. Don't mind helpin someone new out and we play about 7pm CST to about 10-12ish CST. message me if you want to learn more about it and come have fun with us!