Job offer came in! - any advice?

I start on Monday after a long search. I am in Madison, in case local advice matters. I could not have done it without this community. How do you handle the first week?

Thanks for writing this out. I went through something close to it 4 months ago, and it settled down once I kept a simple log of every call and form.

Well earned. Ask questions early, even small ones. People liked it.