Dear Mr. Bristol,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located one series Infantry Unit Records. 1965-1973 in the Records of U.S. Forces in Southeast Asia (Record Group 472) that include daily journals, 1/1/1967-3/16/1970 of the 26th Infantry Regiment, 1st Infantry Division. Some records are digitized and available in the Catalog but not all. For access to and/or copies, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
We hope this is helpful. Best of luck with your research!