Accidently became vilified by the NCR. They showed up in a hit squad and gave me 3 days to be good by them. Any idea on what I should do to "make good," or are they just gonna attack regardless of what I do?

start taking out Legion, that will improve your relations with the NCR.

Thanks, looks like this was addressed in another thread as well.

Kill anyone they send to threaten you. Works a charm.

Do quest for NCR or kill Legion or Brotherhood this improves your rep personally I would do quests for them once your back to netural. Always the final option kill that cocky [censored] hate her threats got fed up on final one and shot her and her lackys in face.

If you really want to have good relations with the NCR then start doing jobs for them as fast as possible. Your status with them has to be no lower than "Mixed" for them to call off the bounty they put on you. A few places you can go to are Camp McCarren(or whatever its called), The Sharecropping Farm, the Embassy in the strip, and camp Golf to name a few.

Also kill Legion and take their ears to Pvt. sixton @ Forlorn Hope. Unless you already wiped them out.

How can you accidentally be " vilified " by the NCR ?

Did you take a dump in Colonel Hui's coffee cup or something ?

Win.

A solution of Jet, Psycho, and Whiskey washed down with an Atomic Cocktail, I blacked out and the next thing I know i'm standing on a pile of bodies, ashes and goo piles in the middle of Camp Forlorn Hope. "What happened, where am I?"
Meh, stupid NCR. I got a nice machete from Dead Sea though, so I call that a win.

This happened to me today, Im doing a bad ass playthrough so doing good for the NCR is not an option. Im only level 8 and I had a go at killing her but I didnt last very long, Im now on the last day and I have still not leveled up. So my plan is to wait very close to a legion camp and when she comes to kill me I can run to the camp and hopefully the legion will have my back. If not im as good as dead as my current best weapons wont take the skin of a rice pudding.

get veronica and get her outfitted with power armor you find near hidden valley in the radioactive pit... equip her with pushy ... that is all the preparation you need and 3 days is plenty of time.

Never thought about power armor for Victoria. It is so obvious and I miss that one.