This is from talking to the curator for the 19th century collection.
We talked briefly about William Law (1809-1892) and his contribution to the Nauvoo effort. Under MSS SC 2562 there is a diary available for the last few months of their interaction, up to the murder of Joseph Smith Jr.
There are also some good 2nd-ary literature materials available, including Roger D. Lenius' Joseph Smith's Red Brock Store, which is available in the Americana section.
Finally, additional economic documents might surface in the Hyrum Smith Collection, Vault MSS 774, Series Three.
Among the locals, I need to contact Brandon Plewe again, and I need to see if the hook-up with Alexander Baugh is going to work out or not.
Finally, if I have a focused set of questions together, I should consider hitting the Church History Library in Salt Lake City after all. Maybe I can do a stay-over in SLC, to make it worth the effort.