Two weeks to spare in the middle of the Pacific

Hello there, I''m planning a two month trip from Cairns to Hawaii in July and August and will need to be buying my tickets soon, however I've had a sudden change of heart about some of the portions of my trip. The original plans are as follows:

2 weeks in and around the Daintree and Far North Queensland.
2 weeks in Vanuatu, with most time spent on Tanna island at the foot of Mount Yasur.
1 week in Fiji (basically an extended stopover as I have to change flights here anyway).
1 week on Oahu, Hawaii (same as above).
2 weeks on Hawaii's Big Island (more volcanoes).

The two weeks in Fiji and Oahu are the ones I'm reconsidering, as I've realised I only really included them because I'll be passing through anyway and would hate to "miss out". Oahu is likely going to be a huge culture shock for me and I'm afraid it might be a throwback to that one time I visited Surfer's Paradise, plus it's the most expensive place on my list by a significant amount. However, there are what look to be some beautiful hikes there, and it could be a nice change of pace to stay in a real city for a while. As for Fiji, I feel like it might just be like Vanuatu all over again, but without the volcanoes. I feel like it's a country I could really love, but I'm having trouble finding anywhere to stay that isn't touristed into oblivion (I know this seems awfully silly coming form somebody who plans to visit Hawaii, but my passion for volcanoes knows no bounds).

So, I now have 2 weeks of my holiday that I'm not sure what to do with, and I'm open to suggestions! I'm leaning towards adding an extra week to Vanuatu and spending more time on Tanna (and hopefully Mount Yasur), but that still leaves me with one week to spare. I'd appreciate any advice you can give!

Between Queensland and Vanuatu, consder a visit to Solomon Islands. One of its active volcanoes, Savo, is easily seen as you fly in, and quite eay to access from Honiara. There is a guest house, Sunset Lodge, whch offers guided trips to the summit, as well as other adventures.
Kavachi is in Western Province, which has good transport links wth the capital, as is Simbo.
Tinakula is often smoking in the distance, between the Santa Cruz and Reef Islands, and I have felt its ash while visiting Luasalemba High School on Santa Cruz. The area has been a hub for considerable seismic activity recently, so it is likely to be cranky. However, flying to Santa Cruz can be a matter of luck rather than good management.

Oh wow, I can't believe I forgot about the Solomons! I may have skipped over it initially due to the sheer scope of the place, but you just made this a whole lot easier. I'll definitely be looking into this, thanks a bunch!

The extra week in Vanuatu is also a very good idea - there's much more to see and experience there than just Yasur on Tanna.

If volcanoes are a priority for you, the island of New Britain in PNG probably has the highest concentration of them in the South Pacific, including very active and accessible ones close to the main town of Rabaul.
http://www.volcanodiscovery.com/new-britain.html
Getting there wouldn't be cheap though.

Fair enough.
With extra time in Vanuatu, Ambrym should be the most interesting island for you, for its combination of a huge volcano and interesting culture.

Yeah, Papua New Guinea would be a dream but I'm saving it for another trip when I feel a bit more seasoned a traveler (and have a bit more cash).

Yeah, I've already planned to spend nearly a full week on Ambrym and am really looking forward to that part of the trip. (:

As for the Solomon Islands, does anyone know if it's the sort of place where I can wing it a little (aside from important things like flights, etc)? I'm realising there aren't many online resources with which to book things in advance and it looks like just getting to the smaller islands (like Savo Island) might require some innovation. The best resources I've been able to find are [url=http://www.visitsolomons.com.sb/]this travel site[/url] and [url=http://exploringsolomons.wikispaces.com]this Wiki[/url], but even they are awfully sparse. I usually like to book in advance if I can, though.

take a geiger counter with you. let us know.
don't eat fish.

I also opt for Solomon Islands, although it is more akin to Vanuatu than Fiji, which is quite different. All three places are fantastic (IMO anyway). I'd skip Oahu, especially Waikiki, which is more like a Disneyland of tourists.

They seem to have ruined the Visitors Bureau website in its latest upgrade. Savo is surprisingly easy, as it is very close to the capital. I organised it through local contacts, but the Visitors' Bureau next to the Mendana Hotel should be able to book it for you. The "resort" is owned by the Speaker of Parliament, Sir Alan Kemakeza, who provides transport by Hilux to a village called Vila on the west Guadalcanal road, and outboard transfers from there. The people who look after Sunset Lodge provide guides and transport to various places on the island. This site might help.
Trip Adviser has some accommodation reviews.
Given that other places will require more organisation, you can fit Savo around Western province and/or Temotu.
It is a very good idea to book your accommodation in Honiara in advance, as it is in short supply, especially the rest houses popular with locals. I can recommend St Agnes and Chester. They have the added advantage of being locally owned and run, so you can ask for help in getting where you want to go.

Anywhere but Hawaii.

Also Please Note-respondent #7 has No Clue NONE

Thanks for all your help Ozziegiraffe, Savo Island sounds like an absolute dream. Will I be able to book Sunset Lodge/St Agnes through that Solomon Island hotels website?

Haha, I still fully intend to visit Hawaii's Big Island, though I'm definitely going to skip Oahu. I have a friend in Hilo, which helps.

Best to contact St Agnes direct.The email is stagnes@solomon.com.sb
If you have difficulty booking Sunset Lodge, Betsy, who manages St Agnes, should be able to point you in the right direction when you get there.

Thanks again! I've booked all my flights so I guess this is locked in now, although after all of this umming and ahhing I've decided to skip Hawaii after all due to the flights being just too much (it would actually be cheaper for me to get a return flight from Melbourne at a later date). I've got 11 days in the Solomons, although if you think that's too short a time I am technically permitted to change my flight times free of charge if need be. I was thinking 3 days in Honiara, 5 days on Suva Island and 3 days somewhere else on the Guadalcanal to do some light trekking, assuming transport permits.

Does anyone know if the Papau New Guinea/Solomon Islands Lonely Planet guide is worth looking at?

Might make that 2 days in Honiara and 4 days elsewhere, actually, as I'm more into wilderness and rural towns (although I really wanna check out the markets).

My preference is to get off Guadalcanal and go to another island, especially if you don't like towns. Transport is quite easy to both Gela and Malaita, and both have accommodation options.
Savo is too small to give a complete eperience of a dfferent island.