I caved and went ahead and gave it to him after like a week.

Mostly because he is really, really into building right now, and I was afraid that by the time his birthday rolls around his interest might have started to fade.

So far he's just rearranged the rooms a few times and built other structures around it. My anticipation is that eventually he'll incorporate it more organically into his wooden block / train track / tinker toy city conglomerate.