This is my idea of what might happen in the next few books...(I will do other houses like the Tagaryens later on)
House Stark
Will once again rule the north -Every noble house except the Barrowtons supports them and will desert the Boltons immediately if there is news of a male Stark heir. The Starks are supported by King Stannis and he has a large army with him. After they are deserted by the Northeners the Boltons will only have a small army in comparison to the Starks. The Lannisters will not be able to help them since they are occupied with besieging Storms End and trying to finish conquering the Riverlands. With the Barrowtons and Freys as their only allies the Boltons will not be able to defeat the *Starks and Stannis. Even if Ramsays letter to Jon is true and Stannis is dead and his army beaten then the Stark loyalists should still be able of winning against the Boltons. The only hope for the Boltons is that the Starks will loose their army to winter....
House Lannister
Will lose everything- Tyrion is attacking Casterly Rock with the Second Sons and due to the small garrison left behind he will succeed in taking it. The Westerland Nobles will not swear fealty to a dwarf (Tyrion) and revolt causing a war in the Westerlands. This in turn will lead the Lannisters of Kings Landing to move their troops away from the Riverlands to take back Casterly Rock.Once the North has fallen King Stannis and a Stark army will march south to take the now undefended Riverlands(if Stannis is dead this may or may not happen depending on whether Bran or Rickon want to take the Riverlands and restore them to their uncle Edmure Tully or Brynden the Blackfish). The Martells will side against them and ally themselves with Aegon. It is unlikely that if House Tyrell is given the option of going over to Aegon that they will stay loyal to the Lannisters. Aegon will take the Stormlands. The only hope for the Lannisters is that the Boltons succeed in holding the North and that the Tyrells remain loyal...
House Arryn*
Once Sansa is married to Harrold and Robert is dead Harrold will join the fighting to retake the North in the name of the Starks. If the North is already taken by the Starks he will probably ally himself with them and march on:*
1. The Riverlands to liberate them for the Tullys(unlikely since they are under Lord *Baelish control)