Get brahmin hides for Balthas
Speak to Balthas in the northern part of Modoc and he will tell you he needs more brahmin hides. Go speak to the jerky vendor about it and he will tell you the brahmins come from Vault City. Go to Vault City and speak to the brahmin herder standing in front of the workbench. Speak with him gently and he will agree to send more brahmins to Modoc. Then you can go back to Balthas to tell him the good news. Note: This quest does not register in the pip-boy.