The majority cemetery inscriptions in the county of Livingston have been indexed at the following web site. http://www.livgenmi.com/cemetery.htm Understand that this is a very early county and over time stones have gone missing for a variety of reasons. The copies of these records is also located at the library in Howell.
When planning to visit the graveyard be sure to check for a care taker of the records for the cemetery you are looking for your ancestor. They often provide valuable clues to your families ancestry.
Good luck in your family search.