Here is the information you requested:
From Cemeteries of Brown County, Illinois
Vandeventer Cemetery, p. 349
Wealthy A. Campbell, wife of Herman Campbell, 18 Mar 1830 – 24 Jan 1893
Herman Campbell, Co. G 12th Ill. Inf., d. 1894, age 72 years.
Ida and Elijah Williams do not appear in the burial records of Brown County.
I just visited the Brown County, Illinois genweb site. I found your generous offer to do cemetery lookups and wondered if you would be kind enough to check for me on:
Wealthy A. Campbell on page 349?
I believe she is a stray from Ohio, born around 1829 and who was once married to Henry C. Campbell in Erie County. He died in 1852 and it appears that her daughter, Ida, married Elijah Williams and moved to Brown County.
By the way, you have a great county site! Thanks for your help.