On Alaska Airlines, you can fly from Anchorage, Alaska; Bellingham, Washington; Oakland; Portland, Oregon; Sacramento, California; San Diego; San Jose, California; or Seattle.
On American Airlines, you can leave from Los Angeles or Phoenix. (American also operates flights from Dallas, albeit for 20,000 Avios a pop.)
Mind you, this works only on non-stop routes (connecting flights give less bang for your buck), and -- because of distance limitations -- converts to two round-trips only from the West. If you’re flying from the East Coast, you’ll have to get to one of those hubs or just pick somewhere else to go.
Alas, that place will not be as rad as Hawaii.