Depending on how much of a history buff your friend is, you might also consider the Mayflower II and Plimouth Plantation, at Plymouth, MA. They employ the method of using re-enactors for guides, where all the guides stay in costume and character for the period. (E.g., Ask them about tea and they look at you as though you had two heads because having arrived in Portugal from the Far East in the mid-16th century, tea had still not made it from Portugal to England by 1620.) It can be either odd or interesting, depending on one’s perspective, but you might consider it.
Philly would require that he has at least one cheese-steak, with Whiz.
Might not be too many lobster in Australia, but what do I know? (It’s on the menu at Outbacks, however 
). I’m pretty sure that Australia is cattle country, so steak won’t be too novel.
For breakfast, you might want to have him try some grits, krispy kreme’s, Vermont maple syrup on pancakes, regional stuff like that.
Boston is a bit out of the way - sounds like they want to do the I-95 corridor from NYC to DC, and Boston is a good 225 miles away from NYC.
We generally only eat Turkey at Christmas time; all the other stuff you listed is readily available and commonly eaten.