L.M.
First, since he offered, allow him to pay for part of the shipping. You can "give" him the difference. That way he doesn't have to pay for all of it, and still has the experience of being responsible for his offer.
About what to include, I have less idea. But since you are the only one from the states, you can focus on things that are different from Singapore. I bet their markets are nothing like King Soopers. And you can still include things that remind the kids we are still similar: sports, school, etc. And remember to get a photo of Stan looking at the Rockies - they are still impressive from far away. Good luck!