Of all the maps, I enjoy Dam Battlegrounds the most. I like that there is such a variety of areas around the map and that it can feel very different from area to area. There is quite a difference in the types of loot throughout the areas and seems like something new to discover as you find yourself somewhere different when you load into a game such as finding apricots in the Red Lakes area on the islands.
So I have been playing "Indiana Jones and the Great Pipe Wrench"! Glad to read that I am not actually doing anything wrong with this method. Beware, extra bullets for Indy's iconic revolver are rare and have a low maximum round count that he can carry spare in the beginning.