If you are experienced with a katana then having a boken is better than a staff. You can use the shape of the boken to your advantage.
That said, if you are one of those people (Like me.) you will have a live blade anyway.
Yeah well, ram it against hard bones, flesh and skulls and you'll see it wont last long...most of my bokkens dont last more than a couple of weeks in sparring(thats for the best). Better get a real blade, or even better - get a gun.
Kid please - dont lecture me about bokken. My bokken were made of caucasian ashwood. If you have the slightest idea what a real bokken sparing is you should know that bokken dont last long in there. 2-3 weeks (considering i do sparring sessions each day) is good result(considering most "cheap bokuto" dont last hours). You bend a steel bar with bokken? Yeah right...whatever...
Mele: in my opinon, a hatchet is a great weapon against the undead the weight of the head adds force meaning it dosen't need to be swung hard when attacking an undead, and if it's a single headed hactcher, it can also be used as a hammer when barricading...
ranged: I would have to go with a simple .22 calibur rifle, usaually the rounds have just engough ounch to get through an undeads head, with n/p at all