I've personally haven't heard naminori used in conversation, but I don't hang out in the surfing crowd either. Google results show that サーフィン pops up more and I have heard that:

私はハワイでサーフィンをします。 Watashi ha hawaii de saafin wo shimasu. I am going to surf in Hawaii.

Or if you are outside Hawaii and want to communicate that you will go there soon and surf:

私はハワイに行って、サーフィンをします。 Watashi ha hawaii ni itte, saafin wo shimasu. I am going to go to Hawaii to surf.

For "We are going surfing":

私たちはサーフィンをします。 Watashitachi ha saafin wo shimasu. We are going surfing.

私たちはサーフィンをしに行きます。 watashitachi ha saafin wo shi ni ikimasu. We are going to go surfing.

For places, usually the state would come before the city, so hawai no honoruru. Or you could just cut out Hawaii because I think everyone knows where Honolulu is:

私はホノルルから来ました。 Watashi ha honoruru kara kimashita.

That's assuming that you are outside of Honolulu telling somebody where you are originally from. If you are in Honolulu now and you are talking to someone on the internet and want to tell them that you are from Honolulu:

私の出身はホノルルです。 watashi no shusshin ha honoruru desu. I'm from Honolulu (lit. My hometown is Honolulu).

ハワイにサーフィンをしに行きます。　　I am going to Hawaii to surf.