Moving to mainland, shippng options?

[hamlet]

My wife's mother is in failing health, so for a time we will need to move to the mainland, Washington State. We used Matson for a 20' container in the past, are there other options/shippers?

Generally speaking, is cheaper to go from Hawaii to the mainland?
It seems, with Matson at least, the price quoted (Nov 2011) is 1/3 of what we paid to move over.

We plan to do our own shlepping, boxing, loading/unloading.

[BradW]

We didn't find it any cheaper to move back than to move over. With container and dogs and rigs, it's expensive.