Faith, I was nervous and a bit apprehensive before our cruise too. Thanks to these boards, I went on our vacation with an easy mind.
I overpacked, mainly on the dressy clothes. I wish I had taken more shorts & capri pants. We had enough clothes so laundry wasn't a problem but we did iron a couple of things that had gotten very wrinkled in the suitcases.
Our cabin didn't have a connecting door, so I am not able to help you there. But I am sure another cruiser will come along to answer the question for you.
Check the capers (daily newsletter your steward will leave in your cabin each night), for activities you are interested in participating in. And be sure to pick up a ship's map from the purser's desk.
My best advice is to try to relax. You are going to have a great time!