I visited Fiji a few years ago.
While its people are lovely, and the scenery beautiful, I didn't feel safe in Nadi. You can see and feel the political tension on the streets, at that time. eg. the lolly pop man at the high school was carrying a high powered rifle, and one of the ATM's we used also had a machine gun toting security guard.
As advised in previous posts. When you arrive at the airport, head straight for your resort or motel.
The high light of my visit there was a guided tour of the Cannibal Caves (the guides themselves had their own stories too).
Second favourite outing was an island hopping boat ride that took us to the island where they filmed "Castaway".
The ex took the kids there earlier this year and said if he went again, he would book accommodation on one of the smaller islands instead.
Have you thought about Vanuatu instead? It's much more laid back. Though it can get a bit shaky at times, with small earthquakes occurring very regularly. They say the only time you to worry about the quakes is when the locals are hanging onto the lamp posts. LOL
The island of Tanna is amazing. You can drive almost to the top of Yassur volcano, walk the last couple of hundred metres to the very very top, and look down into the heart of this active volcano. It's awe inspiring.