If you're in the Kansas City area, it's time for a road trip as a visit to the history department of the Kansas City, KS public library; the historical societies of Leavenworth and Wyandotte County; and the historical societies located in the towns through which the KCL&W traveled. You might also visit the county recorders of deeds in Wyandotte and Leavenworth counties; they will have old records, and probably old maps which will show the alignment of the railroad.
If you're not in the Kansas City area, then again, the first recommendation is that a road trip is in order. If for some reason that's not possible or feasible, then you can contact the same people by snail or email, and see what information they might be able to provide.
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