Using google, I found over 13 thousand records on Family search: URL: https://familysearch.org/search/record/results?count=20&query=%2Bsurname%3ATilkens~
607 Gary Tilkens on Family Search here: https://familysearch.org/search/record/results?count=20&query=%2Bgivenname%3AGary~%20%2Bsurname%3ATilkens~
Tilkens Name Meaning- Dutch: patronymic from a pet form of the personal name Til, Tijl, of Germanic origin.In 1920 the US had:7-11 families in Wisconsin; 3-6 families in North Carolina, Ohio, New York, Texas and California among a few other states with 1- 2 families Source: 1920 US Census- http://www.ancestry.com/name-origin?surname=tilkens
Ancientfaces has about 510 records.. Source: http://www.ancientfaces.com/surname/tikens-family-history/1437884
Maybe some will line up with your family tree and you can add new ones to our WikiTree using some of these sources especially Family Search.