Jason,
A beautiful sight indeed! Congratulations to all involved.
As to burning wood, considering the small distance and low speed you will run the Klondike Kate at, I would not worry too much about kicking out to many cinders. However, when building steam, I would keep the blower low. The blower will kick a lot of cinders out of the stack if you do not keep an eye on it. When running the locomotive ease the throttle open slowly otherwise you will throw a bunch of flaming cinders out of the stack. Wood creates very light ash and it likes to fly. I have watched Eureka throw a shower of sparks out the stack at night, even with a spark arrester. However, it keeps the big stuff in the stack and the small ones that get through burn out before hitting the ground.
I might also mention, that during the day it is hard to see any burning embers coming out the stack, but you will be astonished at how much is glowing at night.
Have a wonderful time this weekend and keep plenty of water nearby .
Dan Markoff