I've only been there once, but I would guestimate
Culver Union has less than 400 marked graves.
The cemetery is about 5 miles north and west of the town of
Culver on an unpaved country road. You can check the map on
http://www.findagrave.com/cgi-bin/fg.cgi?page=cr&CRid=92...;
If I remember correctly, the road to
Culver (90th Rd according to the map above) was paved.
Also, there is a directory in the little building (which includes a restroom).