I am a student and I'm planning on taking the written in September (for my Texas CSR). I've heard that the WKT is pretty easy. The study guide that we have is actually old tests from previous years. They say if you review that you should have no problems passing the test. I've even heard that a lot of the questions are the same. I've been told the verbal portion is the complete opposite.
If you're an RPR, you're eligible to take the test, otherwise you have to get a Statement of Proficiency like Cheryl said. I believe reciprocity is on a state-by-state basis and they haven't approved any states so far, but theoretically it is allowed if they deem the skill test "worthy." I believe you still have to take the WKT regardless though. It's all on their website.