We went to Fiji on a round the world trip and took it as a well earnt break after a month in RMNP and a month in Squamish. Sorry to be the bearer of bad news but I can't imagine much has been developed there and none of the beaches we went to had any sign of boulders or DWS. Where else are you going?
The main island has much of the industry that Fiji has, we were near Nandi, and isn't really what I imagined Fiji to be like. For that you have to goto the hundreds of islands around the place. It wasn't cheap (and we didn't because of time) but there looked to be some great value all inclusive 5/7 day tours with sporting stuff thrown in.
Incidentally I also burnt my armpits so be careful of the Sun. I was trying not to vomit, and failed whilst on a boat. I was laid with my heads supported by both my hands. Armpits were facing up and despite it being a bit chilly my pits got majorly burnt. Bloody hard to live with 'chicken wings' for a couple of days. So take and wear sun cream all over.