I don't think 6 hour for 136 miles is rushing it at all as far as driving time.
And you're right, there aren't any RV resorts on the Denali, but as you said, you've got a Newmar. You would have been inconvenienced by doing a night or two without 50A, water and sewer? Is your generator not working - have you every really used it? If you had spent a little more time looking, there's plenty of places to get out of the road dust and spend an enjoyable night or two
Why did you come to Alaska? You should have taken a tour by air plane and stayed in Glitter Gulch for as much of Alaska as you apparently want to experience.
Bill