Greyjoy Invasion of the North: What would you do?

[Stork in the North]

Following on from my last (and second ever) post which caused quite a debate regarding the Greyjoy occupation of the North, I ask this - If you were responsible for Orchestrating the invasion of the North, how would you go about it in such a way that left you King of the Iron Islands AND the North? Can it even be done? Basically what would you do differently from Balon?
-I would Launch an invasion on Bear Island, giving Asha control of around 10,000 men to do so (half the Greyjoy force). I would wipe out the remaining Mormonts and any of their remaining garrison. If this is carried out then a prominent stark bannerman stronghold is removed from the board possibly without Robb even finding out for a good while. I would establish a command base here from which I could conduct further assaults on the mainland. There's lots of wood here too so we could build some more boats to augment the fleet.
-Once Theon shows up with an offer of a truce against the Lannisters I would send word to Robb that of course I accept this alliance. I would inform Robb that I will use the Iron Fleet to assault Lannisport and that he should totally meet me there to pillage the city. I then simply don't follow through with this promise and it may turn out that Robb loses a lot of men trying to take the city (which without Greyjoy assistance he will be unable to do).
- I send the Iron Fleet to take Moat Cailin same as Balon, except I don't camp there. I leave around 1000 men to hold the castle against Robb should he send Roose bolton North or come himself. With the remaining 9000 men I assault Barrowtown and send word to Winterfell that I dare them to face me. Rodrik gathers his 2000 men and Manderly may muster a force of several thousands too, but against 9000 Iron born playing defence they will have their work cut out. Barrowtown will provide food for my men and supplies can be sent to Moat Cailin (preferably ASAP to prevent Manderly cutting the supplies off). Alternatively I could leave around 2000 men at Barrowtown to defend against Rodrick and have 7000 men march for White Harbor to burn the city to the ground, eliminating the power base of who many see to be the most powerful Stark bannerman.
-From Bear Island Asha could take Deepwood Motte, and then send a force to infiltrate Winterfell and kidnap Bran and Rickon, whisking them off to Deepwood Motte and then Bear Island, securing essential hostages. Also I would torch Winterfell on my way out as a symbol to the Eastern half of the North.
That's all I got right now lol