My plan is to use it as a jab at one of the players who is very secretive. He was belligerent with a powerful alchemist (unaware that he was powerful or an alchemist). So, in order to earn favor so that the alchemist will enchant items for the party, they must travel to the White Wood. The offensive party member must lay on the stone along with another party member their choosing and "return with what they receive."
Of course to many having a telepathic link would be cool but I am not sure that is true for the secretive PC.
And it will be a matter of amusement for the alchemist to know that he drove him temporarily insane.
I may also use this plane shift to move them from G'thal to Jaiman. That would keep them from coming back to the site and continually re-using it. Though I may also just determine that the device requires some time interval before being used again.