Donnelly research trip?

I’m considering a brief trip this summer to visit the Minnesota Historical Society and various Ignatius Donnelly-related sites to research miscellanea for Certain Fathoms. I’ve been able to get a wealth of material via microfilm and interlibrary loan, but nothing beats boots-on-the-ground research. It’s been something I’ve been wanting to do for a while, and now that an opportunity has presented itself I should probably act on it. I’m also planning a trip out east this year, so I may also try to visit Donnelly’s home in Philadelphia, where he lived and worked as an attorney before moving to the Midwest. I’ll post more about these opportunities as details finalize.