First off, I can pick up the reigns on some tasks immediately. I already know the department, as I was user support for them for seven years, the only difference being which side of the fence I'm on.
I already know all the people involved. I know the areas. I know the various systems.
As to how these systems work, and that's all new. Everything in those realms is new.
Also keeping me occupied, touching all those points to get transitioned from one position to another. I need to transfer property, instruct the new guy, wrap up my dangling projects, and just get the little stuff done.
Since I am sitting now, I have adopted the program Task Coach to help me track things. When I stopped tracking my stuff because I was changing jobs, everything got a little too fuzzy for me. So, I've gone to an electronic task list. It creates sub-tasks, which is mighty useful to me.