I'll echo the previous posters. No taxi service at any of those locations, maybe you can get a shuttle to drop you off somewhere but then you'd have no way (other than walking or hitchhiking) to get back to the hotel (very limited cell phone reception, so don't plan on calling for a ride). Why not rent a car in Anchorage or Fairbanks? You can drive easily to the Denali area and the Kenai peninsula.