When you complete Escape! then you can go out and right from the vault, then make your way over the rocky hill above the vault. You should see a silo sticking out of the ground with a barn to the right of it. Head over to there. If you start getting rads when you're near the barn then start looking. For a level 2 character the firelance is a major advantage. ALso, if you go into the barn and go up the stairs, there's a hunting rifle and 11 rounds on the table next to a ham radio.
hope this helps