Mr. King's book, though well worth reading as a memoir, is an endless fount of mostly bad advice. Most execrable IMO is his dismissal of the outline as a writing tool. Some writers get away with "pantsing" everything, but most of us plot more effectively when we think about where we want to go and where each scene fits into the larger narrative.

As for adverbs, King is echoing Messrs. Strunk and White: "Write with nouns and verbs." Their point is that we ought to seek the strongest and most precise words instead of settling for generic ones and trusting modifiers to make them say what we mean. Instead of "she ran fast," we should write, "she dashed/sprinted/fled in terror/churned her legs" or other pithily descriptive words or phrases.

But even S&W acknowledge that good writing has a place for adjectives and adverbs, and they offer examples of their artful employment. I'm especially fond of the surprising usage, e.g. "killing me softly."