I am a descendant of Preston Merritt Atwood and Malinda Frances Stewart. I have information about them and Alonzo Atwood. I believe you have their marriage year wrong. I have 1873 not 1893. Alonzo was born in Littleton, New Hampshire and died in Wisconsin.
Mildred (Mickey) Frances Garrison Atwood of Springfield, Missoouri did much research on these people and when she died she left all of her papers to the Springfield-Greene County Library. If you are able to get to the library it is available for use by researchers. Most of my information came from Mickey's research. Mickey's husband was my mother's cousin and a grandson of Preston and Malinda.
If you want more information you can post a reply or email me directly.