As soon as possible you want to understand the plan of the unit you are replacing and the actions they are taking. Depending how good your links to theatre are (ours are very bad!) you may want to start shadowing what they do. When your team meets up you will have concrete scenarios and actions to discuss.
That's an excellent point, and one thing we did not do at all before our last deploy. It is good fortune that the exact unit we expect to replace is conducting work-ups right next door to our CP, so I will take little bit of a look at what they have cooking. I'm afraid it won't be much though.