Most people arrive in Kathmandu with one spare day, either side of a trek or a flight, and this is what that day is worth. Four of the valley's seven UNESCO monument zones — Swayambhunath on its hill, the royal square at Patan, the Bagmati ghats at Pashupatinath and the great stupa at Boudhanath — reached in a private vehicle with a licensed guide, in about seven hours door to door.
The order matters more than the list. Almost every day tour in Thamel runs these four sites in whatever sequence the traffic allows and finishes wherever it finishes. We run them west to east and finish at Boudhanath in the late afternoon, because at dusk the whole quarter walks the kora clockwise around the stupa and the butter lamps go up in the alcoves. That hour is the best of the day and it cannot be moved, so everything else is planned backwards from it.
Pick-up is from any hotel in the valley at an hour you choose, lunch is in a courtyard restaurant in Patan rather than back at a hotel, and every entrance fee — about NPR 2,600 a head across the four gates — is inside the price on this page. If you want the same valley properly, with Bhaktapur, Changu Narayan and a Himalayan sunrise from the Nagarkot ridge, that is the seven-day version and it is linked at the foot of this page.