Just so I have all my ducks in a row, i need to do a interforest AD migration from 2003 to 2012 and also the cross forest migration of Exchange from 2003 to 2010 and eventually 2013. I am looking to confirm my intentions by asking for recommendations, very high level steps, as to the best way to approach this "beast". I am hoping it is really tame, and not to much of an issue to get done.
Only to use ADMT and exchange powershell to do this. No 3rd party tools.