My recommendations for Napier area would be
Unison - My favourite winemaker of the area, and often the person doing the tastings
Ngatarawa - Often have some interesting bottles open
Vidals - very good range, great Syrah
Te Mata - Specifically for the Elston Chardonnay and Bullnose Syrah
Clearview and Beach House in Te Awanga, whjile you are out that way Kim Crawford
Matariki - Quintology and their Sangiovese
A good website, with map trai is
if you are there on the weekend you must visit the Farmers Market, the Hastings one is bigger and better than Napier
Village Press Olive Oil is my favourite oil, the Picual is amazing
Te Awa has very good reviews as does Vidals, similarly Terroir at Craggy Range
Diva - Havelock North, very nice restaurant, great Maitre'D/Owner
My top tip would be to try and get a copy of the latest Cuisine, and their wine country annual release, a very well thumbed book when i had it.
have a great time
I'd second Stanleyk's recommendations. If you are still around the Hawkes Bay region I'd also suggest Craggy Range and their absolutely fabulous Terrior restaurant. It is pricey and may be a little out of the way of Napier, but definitely worth it.
Kim Crawford is also worth a visit if you get chance.