You should sign up for the Hawaiian Air miles and get their email updates. They post alot of specials especially during the holiday seasons. 350 is a great price but search other sites like priceline.com or expedia or even check with a local travel agency in your area, they can help you shop for the lowest fare. Happy hunting!
Look on Expedia: http://www.expedia.com/I m going to Hawaii after Thanksgiving from L.A.
$350 is more than ok... I went to Honolulu in October from LA and I paid $500 round trip!... good luck on finding really good prices...