He's not sure either of them are actually controlling the dream enough to choose where they want to go, but he would be intensely curious to witness Spike's turning, and meet the infamous Drusilla in person.
However, apparently it's not to be. Even as he starts to prompt Spike to see if he can take them there, everything suddenly starts to go misty and it's as if a gap opens up between them, so that Spike abruptly seems a long, long way away, and receding further with every moment. Then the mist envelops him, and when it clears, he's somewhere else entirely (facing the Blessing, to be precise), and Spike is gone.
((OOC: For once??? *g* Yes, let's. Always good to leave them wanting more!))