Our plans to invade Westeros are currently pretty vague as we're determined to handle Tiamat and the Illithids in one way or another before giving them such an obvious opportunity to stab us in the ass, and who knows how much that'll change. There are some things we can be almost certain about, though.
Uniting Essos: Volantis and Braavos will both voluntarily join our realm (along with Pentos, but who cares). That's
huge. Both of them can seriously claim to be medieval superpowers, and each one of them increases our power by an order of magnitude. If people are sweating about us uniting the Three Daughters, they'll start actually losing their shit once we can claim with a straight face to rule Western Essos. Lorath, Norvos, and Qohor are a bit of a question but it ultimately doesn't matter that much, same thing with Slaver's Bay. We are going to need a significant amount of time to turn all of that into an empire, and it's that period in which wrenches will undoubtedly be thrown into the works.
The Military: The current estimate for the force we need to raise is ten legions, which more than anything is what's causing things to drag out. Training that many professional soldiers takes a lot of time and recourses. On the other hand, they're going to be easily the best army planetos has ever seen. Our naval advantage will be similarly obscene, with Braavos' fleet alone being the best in the world. With the Iron Isles, the Arbor, and Gulltown in our domain, we'll literally rule the seas with utter impunity all across Westeros which gives us a lot of options. We have the best military in the world and the ability to deploy it more or less anywhere.
Baratheon-Lannister War?: Kicking the canon war off early has been discussed. The problem would be making it happen, which may or may not be plausible or worth the effort. Right now we don't even know about the twincest, so we'll see what happens.
Opening Moves: There are a few opening gambits we'll almost certainly take. King's Landing will undoubtedly be the first city to fall in any scenario. It gives us immediate legitimacy for holding the Iron Throne, decapitates the enemy's leadership, has a central location to all of Westeros, and makes the greatest statement. There'll be another salvo of opening moves made as our loyalist lords take up arms. Legions will land in Gulltown, Saltpans, march through the Boneway and the Prince's Pass, while we finally scry and die a bunch of inconvenient targets. Oldtown houses both the Maesters and the Faith, two major foes we need to handle, so Oldtown will quickly be occupied although the 'how' will depend on if the Hightowers bend the knee or not. The Iron Fleet will attack the Westerlands, either raiding the coast or trying to burn Lannisport again, depending on how we judge it at the time. Attack from everywhere, take the major cities, and give our enemy no chance to organize any sort of coherent resistance.
The Campaign: There'll be two stages to this: the high-level PCs dancing around Westeros while the armies occupy the land and crush resistance. I can't predict this with much accuracy due to how many variables there are, although the broad strokes can be predicted. The Vale would be a hard campaign, led by the Royces, Redforts, and Graftons. Our naval and aerial dominance will pay huge dividends but ultimately the majority of the lords there will fight bitterly, so it's just going to take time and blood to pacify. The Reach will also be a mess but the land there means that things will come down to several massive battles rather than a protracted campaign, although with the Seven and the Fey throwing down they won't be simple or easy. The Riverlands will either be a mess or surprisingly easy, it depends on what Bloodraven's been up to. I can't say how the Westerlands or Stormlands will go down, too many variables and not enough information.
Does that give you a good idea of what our plan is,
@mrsean22?