Littlefinger is heading off to woo Lysa to win her troops to the Lannister side. Oh so that'll be it: he'll meet Robb and Catelyn who are also heading that way to try to get her allegiance (if I'm right about that).
Greyjoy has offered to team up with the Lannisters as long as he gets to keep the North. Tywin is not having any of that and plans to ignore him and let the coming winter take care of him. Tywin is also not bothered with sending men to the wall. He's happy to let Mance Rayder keep Robb and Theon occupied. What's the betting that he'll come to regret that?
Tyrion is going to have to be Master of Coin. Since it was Littlefinger's idea, Tyrion suspects a trap. Probably the trap is that there is no money. They're spending it at quite a rate as far as I can see and the King's Landing finances were not in great shape to begin with. The tax take can't be all that great with all the burning of fields that's been going on. Still, this is Tyrion, so he'll probably invent some cunning way out of it, like fiat currency and fractional reserve banking...
Tywin has got wind that the Tyrells are planning to marry off Sansa to the crippled heir of Highgarden. He doesn't plan to allow that to happen. He wants to Cersei to marry him instead. You should have seen Cersei's face! Duff-duff, duff duff duff, da da da da.
But that's not the cliff hanger: there's more! He wants Tyrion to marry Sansa! And soon, before the Tyrells' plans are well known so that Mace can't take offence. Tyrion thinks she's a bit young, and probably won't be that into him. On the other hand, he'd be punching above his weight. And anyway, Tywin says once he's consumated the marriage he can wait a few years until she's grown up. So that's okay then. And Tywin thinks this means Tyrion will inherit Winterfell. Which is fine unless Robb starts having babies with a Frey.
It also turns out that Tywin knows about Robb's snubbing the Freys to marry a Westerling. Now Tyrion thinks the Westerlings are a bit daft to betray the Lannisters (and there's a cool story that the Lannisters so thoroughly destroyed another house who betrayed them that Tywin just has to send singers to sing about that to keep other houses in line -- that's how badass Tywin is). But Tywin thinks they're really thinking one step ahead, which means it could well be all part of a cunning plan. After all, Jeyne Westerling's grandmother was (or possibly still is) a maegi who deals in love potions which may have something to do with Robb's marrying Jeyne.
So to sum up Tywin's plans: Maergery Tyrell will marry Joff, Cersei will marry Willas Tyrell, Tyrion will marry Sansa Stark, Robb Stark will get killed in battle before having children and Theon Greyjoy is just so useless he will get killed by the Winter. This will leave the Lannisters inheriting everything. I bet it doesn't turn out like that, though.
