Talk to Boone about staying overnight at Coyote Tail Ridge.
Talk to Boone.
Go to Bitter Springs refugee camp and repel the Legion raid.
Talk to Boone.
In order to get the quest to activate, you have to exhaust all of Boone's dialogue options about his wife and Bitter Springs. Multiple history points and their associated dialogue can be earned in succession, but you will still have to run through all of it. Boone will usually initiate conversation after earning a point, but not always.
If you have done all the above and the dialogue still hasn't triggered, go back to Novac and make sure to talk to Manny Vargas (the other sniper). He should have a "new" dialogue about Bitter Springs. Exhaust those dialogue options with Manny and it should open up new conversations with Boone.
To determine your current 'history points' with Boone, you may type into the console show "96BCD".nopenness (on PC only).
After completion of the quest, Mr. New Vegas will report the incident on Radio New Vegas. He mentions that two civilians repelled an entire Legion raiding force, and in an interview, a civilian witness said that "God sent us two angels, and at least one of them had a .308 caliber flaming sword of justice with a telescopic sight". If you kill Boone, Mr. New Vegas will mention that he was attacked by a Legion raiding party.
PCXbox 360 After beginning this quest and traveling to Bitter Springs, Boone will sometimes not initiate the conversation necessary to continue the quest and will have only his default dialogue when spoken to.
To be able to continue the quest, open the console and enter the command setstage 001349A7 20 This will skip the part of the quest that's glitched, and allow you to begin the "Go with Boone to Coyote Tail Ridge" section of the quest.
PlayStation 3Xbox 360 Both points you get during 'I Put A Spell On You' may not count; whichever you do first (save the monorail or kill the spy) will count as one history point, but upon completing the other task the other history point will not register.
Xbox 360 If Boone is still looking for enemies even after you have defeated all of the Legion, Boone might say "Let's get through this first," when he was supposed to say the scripted line.
If you have killed all the NCR in Bitter Springs, this quest will fail immediately after the fade on top of Coyote Tail Ridge.
Sometimes, if Boone approaches you saying that he's ready to go to Bitter Springs, but you don't immediately accept, he may become stationary and will not move again until you talk to him and tell him that you want to go to Bitter Springs.