Re: River miles, V'burg to P. Hudson
Though post-war, the following is useful. Note that Cayton makes the distance from Vicksburg to Port Hudson 235 miles.
Frank M. Cayton (1881) "Landings on all the Western and Southern Rivers and Bayous Showing the Location, Post-Offices, Distances, &c." St.Louis. Do read Cayton's introductory "Note" as to confidence he had in his work.