Always nice to see another Canuck !
I too have an old Kona Explosif (mine is an '88) and is in the process of being rebuilt.
I can't help much with the cyclocross except that for many, if they could only have one bike a c-cross would be it even if they do not plan on racing.
The guys in the cross forum should be able to offer enormous amounts of help and riding cyclo-cross will really beat you into shape.
Have fun !