There is only one more section of Birds of a Feather after the Cass section. So you might want to do what I did ....
Save your game just outside of the Silver Rush. Go in. Cass gets killed. You get the final assignment. Go to the warehouse. Survive the battle. Quest ends. You've done the quest. Reload your saved game. You and Cass go off into the Wasteland for new adventures.
B)
But if I reload the game, I still don't the stuff, or is it for achievement purposes? Thanks, I will do this.
Try bringing Cass don't smoke the peace pipe talk with Ol' Jean instead just use a silent kill metheod stealthboy + sneak.
Or take Turbo first talk quickly, turn him hostile, crouch quickly while stealthed and have a strong silent weapon equiped, then shoot him in the cranium.
Here's a link to the magical tome http://fallout.wikia.com/wiki/Birds_of_a_Feather
I forget about Turbo, I never used it. What does it do? What do you mean talk quickly? I am puzzled here. I think I will do this, use a stealth boy and kill them.
There is also a powerful plasma rifle in a room that you might want to sneak in and get before taking them down. Better you have it than them.
I didn't know I could steal the items, since I never tried. I will do this when I am stealthed.
Thank you all for your great tips.