I'm just curious, because that page seems to indicate it's rather easy. Despite our liberal reputation, I've found WA to be more reasonable than many state in a lot of areas, gun law being the one I'm most familiar with.
The only thing we are extra regulatory about is the environment... which in Steve's case, might be a good thing :~D
Here's a couple of charts for comparison. Oklahoma homeschooling is completely unregulated; it's in our state constitution that the education of a child is completely under the authority of the parent alone. State and local government or school districts have no say.
http://www.hslda.org/laws/default.asp?State=OK
http://www.hslda.org/laws/default.asp?State=WA