Can someone explain whats going on geographically between Robb, Tywin, and Jaime? I've looked at the map on HBO.com, and can't figure it out.
Robb was going south obviously from Winterfell, and Tywin is coming north from Kings Landing? Was Jaime going to the Riverlands and House Tully?
Why did Robb have to cross the river at the Twins...it looks like that is going due West. Was that the route to Riverlands?
If so, Tywin thought Robb was coming straight south directly at Kings Landing?
There's only a couple of places an army can cross the Trident river. Tywin's sitting at one of them. They other is the Twins (where Cat negotiated Robb's crossing). Since Robb's plan included lifting Jaime's seige of Riverrun to the west, he had to cross at the Twins or go through Tywin. So he split his forces, sending a token force of 2,000 against Tywin - just enough (in show-logic; it was done a little differently in the book) that - combined with the released spy from last week's estimate of 20,000 men - Tywin would think Robb was coming with his whole army. Meanwhile Robb's going after Jaime, who's a very good single-combat fighter but isn't his dad when it comes to leading an army. It remains to be seen if the show is going to combine the battle Robb fought last night with the battle he fights at Riverrun to lift the seige (two different battles in the book), but if Robb clears Jaime's army away from Riverrun gives him a very important base in the Riverlands.
It also puts him between Tywin and Tywin's home.
So, yes - Tywin's to the east, Jaime's to the west of him, and Robb's coming from the north then turns west with the bulk of his army.