The Sounds are never busy compared to many other places! You'll have a great time. I've spent a lot of time cruising in the Sounds, what would you like to know? Are you based in NZ? I could lend you a cruising guide if you like, or you can probably get one from your charter
company. The central area cruising guide is, as mentioned, very comprehensive.
Dont miss Furneaux Lodge, Endevour inlet, Lochmara, Cockle Cove, ships cove and the Cook memorial etc There are heaps of places - the sounds covers 500 sq miles. Not possible to see it all in the time you have. The anchorages
are sheltered (if you pic the right ones for the conditions - use the guide). The Charter
companies have moorings throughout the Sounds, they are secure and well maintained.
Let me know if I can answer any specific questions.