Thanks for the replies here. Least I know I'm not a lone in thinkin this and I did the trench work on my last world and felt like I essentially cheated, cutting out a path for any/all enemies to be able to get to me. So I'd like to avoid that this time if at all possible. But if the Troll Invasions are just as bad or worse, then I may be forced to take that path and I hate the idea of that, I really do.