Any specific reason on the YK-C versus other areas of the state? Predation has/had been super high in that area with wolves and bears, not sure the turnaround on moose the past few years.
I'd contact 40 Mile Air and see what they have to say since they transport into that area.
What type of hunt are you wanting to do (drop, float, jet boat etc.)? I do not have experience in the area but have considered hunting the area in the past. If you google "Charlie river moose hunt" their is some good first hand knowledge on ak outdoor forums.