I was gonna do this quest but then the Cassidy Caravan quest came up while I was taking her to the Van Graffs. I used a stealth boy to steal the note from the Van Graffs and thought I snuck out undetected but now I just went back to finish the quest and they start shooting me as soon as I enter freeside... is there any way to fix this or did I screw myself over... note: the quest still appears on my pip boy.

Thanks for the help

It appears you may have done just that, with the screwing up. Try waiting a few days and going back to Freeside but the Van Graffs but I don't think they'll be friendly again.

If you're on the PC console commands can help. If not, I'm sorry but I think you'll need to kill them.

The last patch made it so the Van Graff's become hostile if you give the evidence to Ranger Jackson. There might be console commands on the PC that could help, I don't use them much so I don't know for sure. The only surefire thing you can do is reload a save if you want to let Cutting kill Cass.

Damn, oh well I guess it's okay as long as the game is like "choose one or the other"

That is, indeed, the point, which is why they patched it.

I was a bit annoyed at first when I discovered that, as I prefer the diplomatic route whenever available and it's no longer an option with this particular quest pairing, however this is a case where it shouldn't have been there in the first place since the two are meant to be mutually exclusive.