After Pistoia, Beatrice visits Euthanasia at Valperga in September, under the pretence of asking for alms in aid of her pilgrimage. Euthanasia convinces her to enter, but she only stays for a short dialgoue before leaving for Rome (273-6).
I based my placing of Valperga on these passages:

A palace in Florence, constructed from 1489 to 1538. It was built for Filippo Strozzi the Elder, who wanted to use the palace to boast his family's strength, prominence, and political status.

While Castruccio is traveling throughout Italy with the newly crowned King Louis of Bavaria, the two men visit Rome. "They went to Rome together, where the emperor knight him, and he bore the sword of state in the procession from the Campidoglio to St. Peter's, where Louis recieved the imperial crown. He was created count of the palace, senator of Rome, and master of the court. He had arrived at the summit of his glory." (439-440)

The narrator's account Beatrice's travels after leaving Ferrara is vague. She stops twice due to illness, first at "an hospital for pilgrims" (356), second at another hospital where she was "confined for six weeks" (357), but the exact locations of these are not specified. Later, she arrives at Pistoia, Italy, the first specific location Beatrice mentions in her account of her travels after leaving Ferrara:

When Miss Pryor is first given the opportunity to work for the Le Poer family, she realizes that they live in a Yorkshire village (48). Located in Northern England, Miss Pryor left her home and travelled (presumably) some distance to her new post. I had thought that the Le Poer family lived close to London or some other large city, but that was not the case. Miss Pryor and Zillah are removed from society in that regard and they live in a degree of isolation from high society. I wonder if this was a calculated move on the part of Mr. Le Poer, or if the family had always lived in Yorkshire.

Pontremoli is a region in the Northern part of Italy that is a distance from Lucca, 97km to be exact. This was a region that Castruccio conquered and considering the distance it demonstrates the power of Castruccio's army.

The Gates of Somnauth are significant geographically in both The Moonstone and British colonial history. Indeed, the gates itself reflect the entrance to the Somnauth temple which has more significance considering it is likely the site where the Moonstone was stolen, but the gates still radiate a sense of mystery.