I just changed the spark plugs for the first time on my 2002 Santa Fe 2.7 V6. What a bear!! Perhaps I went about it the wrong way, but it looks like the easiest (if you call it that) way to change the plugs in the back is by pulling off the surge tank of the intake manifold. But, that also requires you to change the manifold gasket as well. I went ahead and changed out the plug wires while I was there.
Anyway, if anyone has a different approach, please reply to this post.