Maria was born 1857 in Germany, dau of August Lindenback and Sophia (Unknown). She was married to Christoph Wilhelm Schultz, born April 1852 in Germany, died 4 Nov 1912 in DeWitt County. (Source posted family tree, accuracy unknown). Tree has a date of her death in 1887 in DeWitt Co. They had three sons and two daughters. Adolph, August, Herman, Mary (1882) and Mina Helena (1885-1940). Mina married Heinrich Henneke.
The 1900 Census of Justice Precinct 1, De Witt County
Christop Schultz, born Apr 1852, born in Germany, immigrated in 1883
Augusta, wife, born June 1872, born in TX, mother of 4/4 living.
Marie, dau, born Dec 1882 in Germany, immigrated in 1883
Minnie, born Mar 1885 in TX
Herman Harney, step-son, born May 1883
Edwin Harney, Step-son, born May 1885
Louie Schultz, born Nov 1886 in TX, but shown as being 3 years in age.
Martha, dau, born Jan 1898, age 2.
--Christop and Augusta were married for four years
--Since he immigrated in 1883, dau Marie born in 1882/immigrated in 1883, I would "guess" without any proof, Maria also immigrated in 1883. So, they will not be found in the Census of 1880.
--"IF" Louie was born in Nov 1886, Maria did not immediately die of child birth if she lived to 1887 (as identified in the family tree), but could have died of complications.
The next name in the census, the next page is a Fred "Schultze, age 60, born in Germany, immigrated in 1890. Without other records, unknown if he was related.
If she died on a ranch. The 1900 Census showed Christop as a farmer, but renting his land. It was customary in the 1880's for farm/ranch owners to have their own family cemetery. She "might" have been buried in the cemetery of employers, or in the local poor cemetery. If so, she probably did not have a permanent (cement/metal) marker. In most cemeteries of this era, even if you can find them, markers are broken, missing, destroyed by elements or mischief.
As far as Probate records... Do NOT waste your time looking for any involving her. Probate laws would have allowed her husband to receive any land/inheritance, etc., that was in her name.
--A Will? If her husband was renting land in 1900, there wouldn't seem to be any financial purpose for her to have a will. "Guarandian" records? Unless she was found in a mental institution without family, there would be no guardian records. You have to commit some common sense, knowledge of these factors and the date and place of death..mostly some common sense and some research.
--Obituary? Highly unlikely for that date of time. Newspaper obits at that time were written by a reporter concerning the rich/famous/infamous or victims of crime or accident. A funeral home sometimes identified the name of the deceased and date of service, more of an advertisement than what you would call an obituary. Based on the size of the populaton in the area at that time, she probably died, a local service for her and buried.