“1. If Robb’s starving Tywin out, how exactly is he stopping himself from being starved? And Tywin’s had time to prepare stores, where Robb wouldn’t.” Well, Robb can do some foraging, and he can potentially bring in food from northwards (the area around Seagard and the Twins has been pretty much untouched by Lannister armies) and perhaps from the Riverrun area. I’m not sure why Robb’s in a worse position than Tywin, who only has whatever he’s stockpiled in Harrenhal.