Many years ago a NW B747 enroute to TYO diverted to CYXJ (Ft. St. John) due to medical. Ground staff used fork lift to get on top of a scissor lift catering truck (used for CP's B737-200s) to access passenger door.
Where there is a will there is a way.
Kelowna Flightcraft likely have stairs that would reach at YLW, if that had become necessary.