I've only ever used miles to grab Virgin flights when heading to Hawaii, but options for you which I have done in the past for flight considerations out of the West Coast are:
SFO - HNL
OAK - HNL
LAX - HNL
SEA - HNL
Hawaiian flights out of Oakland are much cheaper than out of SFO and you can use the BART to transfer directly from SFO to OAK and then get your hotel shuttle from OAK, however I found the hotels around OAK to be a bit run down, but its a way to cut down on the overall cost.
Don't forget to look at other options as to your arrival destination into Hawaii, don't limit yourself to HNL, look at Maui or Lihue both of which have mainland flights direct from the West Coast with Hawaiian Airlines, if they tie in with your itinerary as to the island you're staying on, otherwise inter-island flights with Hawaiian are very easy and you just stay airside at HNL upon arrival.
I prefer to travel out of SFO as I just like the area more than LAX or SEA. Also look at options for the flights, in to any of the places I listed above but out of Hawaii don't necessarily look at going to the same as you originated from, there can be differences in the flight prices that make it worthwhile, I've done into SEA and return from SFO, as well as into LAX and return from SFO.
Transferring from LAX to SFO or vice versa is very easy with loads of flights and I've even thrown in mileage runs in the past between the 2 just to grab tier points before my flight back to the UK.
One piece of advice I would say if it's a first time trip, don't attempt to do the entire journey in one go, it's a killer (especially if its all in Economy as my first time was). First time to Hawaii I did LHR - LAX - LIH with only a 2 hour connection in LAX it was doable but with total journey time of 17:30 (inc the layover) and then collecting your hire care and driving somewhere you had no knowledge of wasn't that enjoyable.
The return journey was even worse, kicked out of the condo at midday with a flight not scheduled until 11pm from OGG to SFO getting in at 5:30am then just hanging around for an early afternoon departure arriving LHR early the following morning. Never to be repeated.
Every time I go now I always break it up, overnight in SFO, LAX, SEA on the wayout and definitely do the same coming back. Now I get a flight around lunchtime out of Hawaii getting you back onto the mainland just after 9pm. Then you can spend a more relaxing time before a flight the following day back to UK.
That way you don't feel the need for another holiday just to get over the flights.
If you book any flights directly with Hawaiian Airlines you will have to contact them to get your Flying Club number on your booking as their website wont accept it. Flying Club members get tier points on the flights from the mainland to Hawaii in all classes and if you're in First on the Inter Island flights you also get them, mileage points are awarded for all flights.
Enjoy yourself, and I really hope the car hire prices come down, currently they're ridiculous and I'm looking at £2k for my 3 weeks there next year, who knows how much food prices will be as it's my first time back in a few years!