The below solution come via TrueAchievements by user JordanTheBigBoy
Warning! This achievement is missable if you have not initiated the "Cleansing the Land" quest line. Continue reading for more info on that.
This achievement can actually unlock without doing the devious deeds involved in this quest line. I simply did the quest for "The Way Life Should Be" and then the following quest "Reformation," and this unlocked with it. I never talked to anyone about the bombs, so I think if you just leave the quest open it will complete and unlock with the completion of the other story line. So you can get all three quest-related achievements in one run without backtracking or loading up a previous save.
Just to clarify, you have to have this quest initiated for the achievement to unlock after completing "Reformation."