Hi Berdine, I first found Susan, her husband Perret and children including Tilden in 1880 living in Callao, Macon Co., MO.
A Tilden Warden on Sept. 12, 1918 was living at 2 Harrisburg, Linn Co., OR. He was born 27 Dec 1876. Occupation-Merchant, self-employed. Nearest Relative=mother, Susan Warden at same address as above. Source: World War I Draft Registration Cards 1917-18, www.ancestry.com.
In 1920 Susan and Tilden were living in Rowland, Linn Co., OR. Tilden Warden, head household, b. IN, 43 yrs old, widower, retail merchant general. Susan Warden, b. OH, 82, widow.
A Susan Warden died 14 Jan 1922, Linn Co., OR per death cert #12. Source: Oregon Death Index 1903-98, www.ancestry.com.
A Tilden Warden died 4 Sept 1922, Linn Co., per death cert #196. Source: Same as above.
The Linn County, Oregon Historical Museum has obituary records. Go to www.co.linn.or.us/museum/genealogy/index.htm .
I'd request their obituaries first because they might say where they were buried.
Another source of info might be the Linn Genealogical Society, www.lgsoregon.org/ . Successful Searching!