Doesn't matter about the tag requirements where you buy, it matters about the tag requirements of the state your vehicle is tagged in. If Alaska doesn't require tags, then you won't need any.
I do agree that prices in CA due seem to be lower and definitely about the rain issue.
Also, make sure you know your weights and how much you can actually carry. Don't forget, dry weight of a camper is usually about 1,000# less than the weight wet.
One of the nice things I like about Oregon are the weight scales are available for anyone as long as they aren't being used for trucks. They look off, but turn on as soon as you put weight on the scales.
