UCF does have the full text on microfilm of other U.S. newspapers, the earliest of which is the Boston News-Letter / Massachusetts Gazette (1704-1770). Very few of the newspapers have indexes, so you'll be researching by dates.
The listings for each state include links to some free online resources, some of which provide indexing or full text. Some of the indexes provide full text for a fee. For example, the indexing of the Chicago Tribune is available online (1852+) with individual articles available for $4. NOTE: The full text of the Chicago Tribune (1849+) is available on microfilm in our library.
The University of Central Florida is a member of the Center for Research Libraries which has a large collection of newspapers available through interlibrary loan.