New zealand

I think your question may not be specific enough. It would be helpful to know where you have already been that you don’t feel a need to return to.

There is certainly a lot to do in and within driving distance of Rotarua, so it could be a possibility.

There are way too many options for the South Island for me to suggest anything without knowing more about what you are looking for. But even so, I might suggest two one-week stays, if you definitely don’t want to travel around.

Yep it's pretty hard to to answer without more info from you.
Rotorua is pretty central and has a stack of things to see and do. It can be a bit of a money mucher though. Have you been there before?
An alternative might be somewhere up North. I really enjoyed Paihia and the Bay of Islands. Plenty to keep you engaged for a week.

Queenstown is probably a logical base on the South Island. It's pretty central, easy enough to access Fiordland, the Mt Cook region and also the West Coast Glacier villages and has plenty to see and do itself. It is Tourist Central and also a bit of a money muncher.

We spent two weeks just on the North Island. I don't recommend staying six days at one place. Rotorua was nice and we did spend 2-3 days in that area.
We loved Wellington.

If you can share more details about your New Zealand trip and your plans, we can advise you better.

I can't imagine anywhere on the South Island where I would want to base for two weeks.

I loved this area of the South Island of New Zealand when we were there:

There is a lot to do around there, hiking, kayaking, and lodging.

To find the closest town to Queen Charlotte Sound in New Zealand, consider the following points:

Picton - The nearest town, located just a short distance from the sound.
Havelock - A small town to the south, known for its green-lipped mussels.
Bluff - Located further south, it’s a port town but not as close as Picton.
Nelson - A larger city to the northwest, but farther away than Picton.
Wellington - The capital city, located to the south, but significantly farther than nearby towns.

Oh, and don't forget about Abel Tasman National Park, it honestly is one of the most beautiful places I have ever seen in my life, and I've traveled to a lot of beautiful places around the world.

We stayed in Nelson and took a bus/ferry out to the park.

If it's scenery you crave- beaches and flora, I'd suggest starting from Auckland. Drive up to West Coast of Northland, see the enormous kauri trees, Go to the tip of the island to see the mystical departure point for spirits and where the Pacific Ocean and Tasman sea meet. Down the east coast thru and past beautiful beaches. Waitangi, Russell are beautiful, historic towns, places and you can see authentic Maori carving. October should be quiet as its term time for NZers. Although I like Rotorua, a week may feel like too long. However the hot baths are very therapeutic. I can't think of where you would use as a 2 week base in the South Is. Day trips would mean very long drives, no matter where you were.