I _really_ like your exploration of Calhoun's character in this alternate scenario. I believe there is a recent biography called
Calhoun: Nationalist or something like that.
...OK, apparently it's Vol. 1 of 3, the other two being
Calhoun: Nullifier and
Calhoun: Sectionalist; it was written in 1944; and it's the standard biography for beginning any study of Calhoun

. Well, Borders had a shiny new copy of it last time I was in there. May be worth reading if you're going to write a Calhoun-centered story. Either way, I am very, very interested in seeing how the US evolves without the polarizing figure of Jackson. It sounds like the Era of Good Feelings gets a few more years? Will that mean that slavery is complacently accepted for a bit longer?
I'll bring up Indian Removal again, because that always seems like such a preventable tragedy. If Calhoun follows the economic policies of the nationalists, that may imply that he also follows their public lands policy - they wanted to sell land at a moderate pace to encourage higher prices and thus more government revenue. This would have led to a slow, steady rate of westward expansion. The Jacksonians preferred to sell land at a breakneck pace at rock-bottom prices in order to encourage rapid growth. Hence their passion for removing the Indians completely.
what about that movement called IOTL "Jacksonian democracy"? I'd imagine the forces are still present in TTL's USA that lead to mass political participation on a new, large scale. Who will be the first to take advantage of this new national fervor? Will we have "Harrissonian democracy"? "Van Burenian democracy"?
My one criticism is still with the maps. I still think it's more interesting to divide the Mississippi-Alabama region differently, the way you had it at first. And the election map seems too tidy geographically - in OTL, each candidate had his region of strength, but the votes did not break down so neatly by region as you have it. Also, Illinois, Louisiana, Maryland, Delaware, and New York apparently divided their electoral votes. I'm looking at this map, by the way:
http://commons.wikimedia.org/wiki/File:ElectoralCollege1824-Large.png.
Other than that, great job, and i'm interested in reading the next installment.