Fiji - 4 days - Recommendations?

Hey
I am a single young female and I'm going to be in Fiji for 4.5 days (landing in Nadi) and I was wondering if anyone has any recommendations?
Is Octopus Resort worthwhile? Should I stay closer to the airport since I'm not staying long?
Is the only way to get to the Yasawa or Mamanuca islands via the flyer? I have no travel plans and I leave in 10 days. Could someone help me out?
Also, a friend recommended a small hostel on Waya that has some of the best snorkelling and at low-tide you can walk over to Wayasewa.

Do you have to book ahead of time or can you show up...many do not have e-mail links or websites.

Finally, is their a particular hostel that is recommended in Nadi for my last 1.5 days.

Waya is an attractive island. Some photos here. It takes 2-3 hours or so to get there on the Flyer. I believe that Octopus resort will arrange its own pickup of guests.

Octopus is the best 'resort' on Waya. The others are lower budget. The one at the south end of Waya (I forget its name) isn't a small hostel, just a small resort with a few (6-8) bure, a common eating area, snorkel equipment for rent. It has the best snorkelling at that end of the island -- easy to get to from the sandbar. But the sand also makes for slightly murky conditions if the sea is rough.

You can't just show up because the resorts send boats out to the Flyer which waits offshore (no docking facilities). If they don't know you're coming, there won't be a boat to meet you. So, one way or the other you have to contact them ahead of time to let them know you're coming. Probably you can do this with one of the travel agents at the airport.

If you're worried about time, or just want to spend less of it getting to and from your island, then stay at one of the Mamanucas -- they'd all be better than staying on the mainland near Nadi.

Thanks for your help!

Octopus was awesome and I really, really cannot wait to get back to Fiji! I would recommend that you spend the night before you fly out on the mainland - everything runs on Fiji time regardless of whether you need to get some where or not!!