You don't mention how much you already know and what you are looking for but from census records, I can see a few things.They were in Kansas as early as 1910, and Floyd worked for the Railroad in several different jobs.As a machinest in a RR shop and as a foreman on an engine (shop, maybe). and earlier as a section hand.
Floyd's age varies some but is most likely Jun of 1878 and born in Kentucky with both parents born in KY.
Elsie M was born in Nebraska and one place her parents birth places are both shown as Missouri, and in another it shows her father born in Illinois.I tend to think Missouri is correct.I think I see them in Colorado before coming to Kansas, but that may not be right. Looks like they married about 1906.
I see children all born in Kansas, Cleo (male) abt 1907, Dorothy abt 1911, Chester (Jack Chester) abt 1915 and Ruth abt 1919.
A quick search appears that the Allens may be from Elliottsville, Breathitt, Kentucky, but I didn't spend any time trying to confirm this since I didn't know what info you already had.