No 739ERs on the way. All new deliveries will be 800s.
I think there may be certain days in the year when the flight won't be able to operate because of winds. The route is about as long as our ANC-ORD run and I've heard of them having to make a fuel stop now and then.
Here's from landings.com:
Route between KSEA and PHNL: Distance along great circle: 2675.1 statute miles, 2324.7 nautical miles, 4305.2 kilometers Route between PANC and PHNL: Distance along great circle: 2778.4 statute miles, 2414.4 nautical miles, 4471.4 kilometers Route between PANC and KORD: Distance along great circle: 2836.9 statute miles, 2465.2 nautical miles, 4565.5 kilometers
Route between KSEA and KMIA: Distance along great circle: 2719.6 statute miles, 2363.3 nautical miles, 4376.7 kilometers
So you see it's not much further than some of Alaska's other routes.