Thanks, folks!
It was his birthday, yesterday, and everyone seemed to be thinking the same thing: he wound up with 12 models (plus one lego set - an airplane.)
He did want to learn about decals. I'll see if I can find something that fits.
I was thinking about the tracks, too, but was so excited to take it to the office with me that I didn't insist. I think we could use those tracks as a lesson in washes and drybrushing. Maybe I'll take it back home. It just feels like magic to me and I don't want to change a thing.
At this time he has no concept of the internet. I try to keep my kids from having a web presence (and I'm a computer engineer - go figure.) But he knows how proud I am. Dear God, we have fun together. What a fantastic little kid!