I guess it's good for training. I've ridden the Katy twice and never wanted for food or cooking gear. Except in really remote areas I've found it best to "live off the land" ie restaurants and convenience stores. Something you may consider is a 3rd water bottle as not all trailheads have fountains and those that do may be turned off early in the season.
Pick up a brochure at the trailhead when you start and it should tell you what each town has. Or you can just print this.
http://www.mostateparks.com/katytrail/services.htm
Good luck.