Alright, here's my King's Landing intrigue action idea. This will require Viserys' personal participation, but I belive that it's worth his time.
@Azel - any advice or criticism?
Last time we went to KL the obvious focus was on dealing with the Wildfire and those who produced it, and so our Red Keep trip was something of a short afterthought in which we only half-assed a 'spy network' and got rid of the rest of the Substance. This time, we should make a concentrated effort to accomplish several objectives focusing on information gathering, threat removal, and asset acquisition.
First of all, Info Gathering. We should check in on our new friend the 'innkeeper' and figure who he's told about last time. We can decide whether to climb the ladder or turn him into a serious asset from there. We should also make effort to learn about King Robert, Jon Arryn, the Small Council, etc. We can't rely on canon knowledge due to the number of changes at this point, and knowing what makes our enemy tick is key to being able to manipulate them. Figuring out which one of them is working for Mammon is also important, as well as updating ourselves on the Baelish situation even if he isn't the rat.
On to Asset Aquisition. The two key figures I think we have a chance of snagging are Ser Barristan 'the Bold' and Ser Jaime 'The Kingslayer.' Just to be clear, I'm well aware of the fact that there's no guarantee that it'll work, but I believe it's worth the negligible risk - if things don't work out we should just be able to wipe the memories of the event from their minds, and Viserys is a social combat master. With Ser Barristan, I'd attack the honor of the Kingsguard. He just flipped sides while Rhaeger's corpse was still fresh and has been leading the Usurper's travesty of a Kingsguard, he has no goddamn right to judge the Kingslayer who arguably has held truer to his oaths than Barristan (dropping the Wildfire bombshell is a risk, but ultimately not serious due to it all being gone and there not being any reliable witnesses). Basically, my plan is to state that he's not going to be able to just switch sides again when we inevitably take King's Landing and that he should either A. - do that Arstan Whitebeard thing until he gets his honor back, or B. joins us. Revealing that we have no intention of reforming the Kingsguard due to being so disgusted with the institution could work. In total, the idea is less to get him and more to deny him to Robert, preferably in a really public way.
Jaime is going to be much trickier, but I believe we can pull it off. Judging by the fact that he's heavy drinking and spilling the 'killed Aerys because wildfire' secret to a more or less completely random stranger, I think it's safe to assume Cersei's ditched him. Approaching him does have the second objective of finding out about the Twincest debacle, which would be incredibly useful to know IC. Getting the Baratheons and Lannisters to split into a civil war at the right moment is great for us pretty much no matter what. As for Jaime himself, it really depends on how much his characterization has progressed - the key point here will be his attachment to Tywin. Everything else can be handled, including his children and the rest of the Lannisters, but Tywin's dying horribly no matter what, and although there's hardly any affection between them it'll still be something else to betray your own father and family. Jaime did hold genuine loyalty to Rhaegar and he feels horribly guilty over the fates of Rhaenys, Elia, and Aegon. It's complex, and I genuinely don't know how things will work out, so we'll consider looting him a secondary possibility while the primary objective will be to IC discover the Twincest.
Most important of all is rescuing Belarion The Cat so we may give Rhaenys the best present ever. It shouldn't be that difficult to find him with a Wayfinder in the Red Keep.
Finally, Threat Elimination. We need to murder Varys. It doesn't even have to be subtle, just kill him in a way that can't be reversed. Or better yet, capture him. That way we don't have to worry about him getting revived and can squeeze every bit of knowledge out of his skull. I wouldn't count on that being easy, though, since he's going to be on alert since we rescued one of his maimed kids. If we discover Mammon's catspaw, we may want to just rid ourselves of them depending on who they are and how much of a threat they actually pose. Other than that ... wow, there really isn't much that can actually threaten us in King's Landing, is there?