There isn’t much that hasn’t been said already about the Forbidden City. How it was the seat of the Chinese Emperor from the 1400s all the way till 1911. How it survived the marauding hordes of the Cultural Revolution because Premier Zhou Enlai sent military guards to surround and protect it.
It’s still an overwhelming sight to behold today… that is, if one can get around the hordes of Chinese tourists and their tour guides with loudspeakers blaring at full volume.
That’s right – I shall speak the unspeakable. Touring the Forbidden City is an exceptionally unpleasant and enervating experience. Most of the tour is spent trying to work around the thousands of people – largely Chinese – in the palace complex.
That’s ok in the outer palace – where there are immense courtyards flanked along the north-south axis by grandiose and majestic palaces. But once past the threshold into the Inner Palace – where the Emperor, his wives, concubines and sons resided, the crowd becomes intolerable, especially since these gardens in the Inner Palace had been known for their tranquility and charm.
My recommendation is to walk through the Forbidden City as fast as you can, slip into Jingshan Park 景山公園 just to its north, and hike up the adjoining Prospect Hill to the Pavilion at its very top. There, together with the relatively fewer numbers of Chinese tourists who deign to make the climb, you can enjoy a breathtaking panorama of the entire Forbidden City complex, in (relative) tranquility.
Thereafter, a walk around the Palace Walls and the Moat is an absolute delight, because only here, just outside the palace, can one get a sense of Old Beijing 老北京 – it is inherent in the solitary, elegant watchtowers that flank the old palace walls, and in the many flowering cherry trees and trailing willows that line the banks of the moat.
It is also, more importantly, infused in one of last remaining tracts of hutongs 胡同, or traditional courtyard houses, that sit along the edges of the wall – they are what remains of a vast Chinese city of courtyards and pavilions that Beijing once was; and which it has lost sight of in the race to develop.

Just past the Noon Gate sits an artificial River that cuts through the Palace. This is one of the bridges across the river.

The Hall of Preserving Harmony 保和殿. This hall together with the Hall of Supreme Harmony and the Hall of Central Harmony constitutes the Outer Court.
I went to Beijing in August 2013 and without planning too I did almost exactly what you just recommended. And the view from the pavilion on the hill north of the forbidden city was indeed the best part, that and walking leisurely thought the park it self. Al tough the walk past the walls and the moat was interrupted before we had really began by a huge downpour that lasted for hours…