Process Servers

I am about to have the birth mother served with the abandonment petition and citation to appear. My problem is that I live in Northern California and she lives in Los Angeles county. I was wondering if any one has a reccomendation for a process server. I was thinking of starting with the sheriffs department serving her. She will probably be a challenge since she doesn't work, she doesn't have a regular home, and doesn't have a phone number. I only have the address of her parents home and that is where her other two children live so she does go there a lot. Thanks for any information of precess servers in the LA county area.