One of the most difficult migration paths for SharePoint is from version 2007 to 2010. Not so much due to the technical requirements concerning things like content database shift, Web Application shift, Site Collection review, Third Party review. But more on the actual sequence of events, which if not worked out completely could leave people attempting to go this in a pickle! To help, I’ve provided a map which I have used with several customers which allows me to produce key documentation and at the same time keep them involved in the process.
To assist the map, there are two project plans attached in 2007 / 2010 / 2013 formats, which allows you to set time-frames against each of the sections.
Note that these are generic. You must use your own judgement concerning things like Third party products (and what you wish to do with them), what must happen to content on the document lifecycle trail (i.e. old sites, archived content), and what must happen to any control processes surrounding things like security (who should have access to the new world).
This is particularly related to testing, and again, you should adopt a generic approach first then tailour it to your own requirements. Read through my Verification and Validation article to give you ideas of what should be in your testing plans (which will encompass technical and non-technical concerns).