Toledo is a city you cannot see from inside. It is built on a granite spur inside a meander of the Tagus, and the streets are too narrow and too steep to give you the shape of it. The ring road on the hillside opposite — the Carretera de Circunvalación — is where you go to understand what you have been walking around.
From the viewpoint the city presents its whole south face: the square block of the Alcázar on the skyline, the cathedral tower beside it, the pinnacles of San Juan de los Reyes at the far end, the medieval walls dropping to the water and the river running through its gorge below. It is one of the standard views of Spain, and it is free, unfenced and open at every hour.
Getting there is the whole problem. It is about 2 km from the historic centre by road, roughly ten minutes by car or taxi, with a free car park of about fifty spaces. On foot it is a 40–50 minute uphill walk from the old town along the ring road — pleasant in spring, punishing in July. Local guides report that city bus line 71 runs along the Carretera de Circunvalación with the nearest stop, Doménico, some 10–15 minutes’ walk away; there is no bus to the viewpoint itself. The tourist train and the tourist bus both leave from Plaza de Zocodover and both stop here.
Timing. The city faces you and the light comes round onto its front through the afternoon, so anything from mid-afternoon onwards works and the hour either side of sunset is the reason people come. After dark the monuments are floodlit and the car park empties.
Two notes to save you disappointment. There is not one viewpoint but a string of them along the road, so walk a few hundred metres and pick your own frame. And El Greco’s View of Toledo, the painting everyone half-remembers, is generally identified as a view from the north side of the city — not from this hill.