joannalannister:

I was thinking about how Tyrion might assault Casterly Rock, and we all know about the drains and cisterns. I think it has to be through the drains because if, like, you were trying to drop down into one of the Rock’s cisterns, via dragonback or s/t idk, you would have to deal with arrows being fired at you, and the Rock’s defenders might be more alert if they suspected that someone had gotten inside, which is why I think the drains are the way to go. 

But once you get inside, I’m trying to think about the most effective thing you can do, because even if you raise the portcullis and let the enemy in through the Lion’s Mouth, they would still have to fight their way up through the unfamiliar tunnels in the dark and the place is huge so rooting out the Lannisters like that would be a bitch, and it would take too much time, and if we ever get to this point, I think the story will be running out of time.

So if I were Tyrion, and I got inside, I think my main objective would be Tommen, similar to what Visenya did at the Eyrie with Ronnel Arryn. And now I can’t stop thinking about this: "But Tommen … why would I harm Tommen? He’s a good lad, and mine own blood.“ Because, unlike Sharra Arryn, I don’t think Cersei would surrender. Ever. :///

Depends on how many defenders are left and how well led they are (after all, given that the history of the Lannisters starts with them taking the Rock through subterfuge, it must be possible). Daven probably took a good deal of the garrison with him to besiege Riverrun, and we don’t know if Ser Damion is any good as a commander.