Hello Ms. Maine,
We would first recommend contacting the Historical Society of New Mexico or the New Mexico Commission of Public Records. They will likely have, or know who has, pertinent records relating to Santa Fe in the 1850s. You may also be aware that there is a memoir by James Josiah Webb that could prove useful. A good strategy is to note moments when he would have interacted with governments such as through censuses, taxes, and licensing.
As far as records that the National Archives has, below is a selection from the Guide to Federal Records webpage concerning Record Group 49, Records of the Bureau of Land Management:
49.7.8 Records of the Office of the Surveyor General of New Mexico
Note: Records designated as in Santa Fe are on deposit in the New Mexico State Archives. Address all reference inquiries concerning these records to Chief, Archival Services, State Records Center and Archives, 404 Montezuma Ave., Santa Fe, NM 87503.
Textual Records: Letters sent, 1902-7 (in Washington Area). Letters received, 1854-90 (in Washington Area). Correspondence, 1894-1910 (in Denver). Field notes, 1855-81 (in Denver). Land claim case files, Office of the Surveyor General, 1854-92 (in Santa Fe). Case files, Court of Private Land Claims in New Mexico, 1892-1912 (in Santa Fe). Spanish and Mexican land grant and related records, 1685-1846 (in Santa Fe).
If you would like some assistance with federal records, please contact the National Archives’ reference department at this e-mail address: firstname.lastname@example.org. They will also be able to suggest other record groups that may have something regarding your ancestor. Unfortunately we cannot conduct all the research you may want or need but we will happily get you started and help you along the way should the resources merit a visit.
We’re sorry that this reply hasn’t reached you before your trip but hope it will still be useful.
Best of luck!
Compiled by Alex Champion