The Star Showdown: If she survives, she tells you that Tomas was insane and wanted some sort of stars. If you mention that Tomas was looking for Sunset Sarsaparilla star bottle caps, once the dialogue ends she will say she needs time to compose herself and remain friendly. However, this friendliness is a ruse and she shoots you in the back. If you have at least 7 Intelligence, you can see through this and gain 25 XP.
If you don't mention the star bottle caps, she'll start walking to the Mojave Outpost. She'll only make progress while you're in the map area but once she arrives at the Outpost she'll remain there even if you leave the area and come back.
If Tomas's journal is looted from his body, you can start the dialog with her again. During the second dialog, Terrifying Presence can be used to demand her to hand over all star caps without opening fire; otherwise she will turn hostile.