I was walking up along Corso Garibaldi, which itself was obscure and lonely enough, when I caught sight of the sign which pointed to this park. So I heeded it, and after two tiny lanes and through an iron gate, I ended up in paradise!
The Parco di Ponte San Angelo is a very well-hidden gem in Perugia. Unlike the noisy and tourist filled park at Piazza Italia, here you can have the whole place to yourself. And the view is a fierce competitor to that at Piazza Italia. Here, instead of seeing Assisi, you get a great view of the Perugian plains, including a lovely faraway hill, one of the "legs" of the star shaped Perugia, with countless charming houses on it.
There are adequate benches and even a nearby WC. To get to the park, from Piazza Fortebraccio, head uphill along Corso Garibaldi about 300 meters uphill you will see the sign that directs you to the park. Then you're just one minute away!