Complex sentence: Their only unmarried daughter, Willie May Kell (1888-1980), thereafter occupied the house until her death, after which time the Wichita County Heritage Society purchased the property and converted it into a museum, which opened to the public in 1981.
Split into simpler sentences: Their only unmarried daughter, Willie May Kell (1888-1980), occupied the house until her death. The Wichita County Heritage Society purchased the property and converted it into a museum that opened to the public in 1981.