Contrary to what Gardyloo wrote above, it is impossible to get from Anchorage to Denali in 4 hours.
Not impossible, but you're right, not likely.
Last time I made it in four hours I was highly motivated because my not-yet-wife was having a gall bladder attack and the PA in Healy said it was either go-fast or he'd call in a medevac from Fairbanks.