Cornfed

Hi, I recently purchased a 2003 ES300 that has 83k miles on it. Overall it's in great shape, but I looked at the plugs at they appear to be original and will have to be changed in the future. I have looked, but not found a definite process to access the rear plugs. It looks like the upper intake manifold will have to be removed. I would like to know if anyone else has any other suggestions or tips. Thanks