Yes, Pele has been active lately, but VOG usually isn't a problem on the Kohala Coast. And when it is, if often extends up the island chain. Doubt that it would ever be much of a problem at Turtle Bay though.

I've experience VOG all the way over on Oahu but on the southern side.

Turtle Bay should be fine in September. You will need a rental car to get there and back to HNL, and you will need to allow time for that drive. (You can see a lot of Turtle Bay in the sophomoric movie "Forgetting Sarah Marshall".) I would consider booking two or three nights at Turtle Bay in the middle of your stay, with the other nights on Waikiki.

Are you flying from the west coast of the mainland? If you live farther than that, I'd really think hard about spending the time and money for only six days (five nights?). Hawaii is fun with a baby, too, if you'd have more time after he/she is born.

we're flying from southern california for our 6 day trip. since were only going to one place we hoped that would be enough time. my like turtle bay-- my husband thinks it's too remote and therefore prefers south shore kauai, so we're leaning toward that

Poipu is quiet, but less so than Turtle Bay, and you can spend a day touring Kauai's most gorgeous north and/or visit Waimea Canyon. We've enjoyed the Sheraton, Poipu Kapili, and Kiahuna Plantation in Poipu, although not recently. (We bought in South Maui in 2001.) The Hyatt is a luxe property in Poipu.

Good choice! Be sure and visit the North Shore beaches one day, should be calm in September, the seas do not start to transition until October.
Canyon another day is a must, try and get there a bit early as the fog rolls in often after 9-10am. I would drive north to Koke'e State Park first and visit the Kalalau Lookout, then stop at the Canyon on your way back down.
For lunch I like Wrangler's in Waimea, others prefer Shrimp Station.

Great advice chisue and jamie! we will definitely visit the canyon and the north shore. it looks like we're going to stay at the hyatt in poipu.

We stayed at the Hyatt a few years ago - it's a great property!

The Hyatt in Poipu is one of our most favorite places in the world. The resort has nice restaurants and the grounds are gorgeous. Lots of people like the north shore of Kauai, but I prefer to do a day trip to the north shore and stay on the south shore.

You're going to have an awesome time!

Good choice, kbhejna!

We had a nice dinner there many years ago.

Love the Poipu area! You will have a great time. I have a trip report from our trip in February this year.

http://sulynnchen.com/travelblog/?page_id=1285

I've also stayed at Turtle Bay for a few nights (pre-renovation), but I found that when I'm on Oahu I like to be in the thick of things. Turtle Bay was a bit remote for me, considering Haleiwa was about a 30 minute drive away, and the road is pitch black at night. It's a beautiful resort though and I think the villas are really pretty so I'd combine a stay in Honolulu with a few days there.

Trip report from a few years ago but we did stay at Turtle bay for the last 3 days of our trip: http://sulynnchen.com/travelblog/?page_id=299

Thank you for the trip reports tifa2276! good to hear you guys liked the hyatt. i think we might do a big family reunion at turtle bay eventually -- but it sounds like its not right for what we want for this trip specifically.