Four days is enough for Meghalaya if you stop trying to see all of it. This route trades driving hours for time on the ground — a morning in Shillong's markets with someone who can explain what you are looking at, an afternoon in a Khasi village, a full day on the Sohra waterfall circuit and a village walk at Mawlynnong.
It suits couples, solo travellers and anyone who would rather eat jadoh in a local kitchen than tick off a viewpoint. Pace is relaxed, mornings start late enough to be civilised, and there is room in the itinerary to change plans if the weather turns.