You're mainly on the southern Broads in your itinerary which is often less busy, hopefully easier to get a mooring space as they do fill up quickly. However I've always preferred the Northern Broads as seem to be more villages to visit.
Packing - I'd advise using soft holdalls rather than suitcases. Storage space for them is often under the beds/sofa benches. Lift up the mattress.
Norwich is lovely although long walk up the hill from the moorings. Great Yarmouth not so much. You don't say if you have children with you and their ages.
Wroxham is worth a visit, if only to marvel at how many shops are called Roys! There is a reason for it. Maybe stop on your way up and do the food shop. You are prob going to drive through it on the way to the boat.
Waterproofs are needed for the people mooring up not the driver. Motor boats have steering undercover.
Food - always bacon for breakfast! It's not a boating holiday unless you can smell bacon wafting out over the moorings in the morning!
Take up the offer of life jackets from the boat company for ALL members of your family. It's often deeper and colder than you'd imagine should you fall in.
Can't remember where they are located on the southern broads but the Broads Authority have visitor centres doted around. Worth a visit - they have activity books for children geared around the Broads.
Enjoy!