I would love to hear about this massive international displacement from the people directly affected.
Yes!
(First of all, do you know this person? You guys phrased your questions really similarly, and on similar topics...)
The thing is, I've been doing a LOT of searching and I haven't found any books which specifically recount the first person stories of those affected. I honestly find this astonishing, especially since there are a LOT of first person sources which have been used to compile the information that scholars now rely on in their discussions of the expulsion. It could be I just haven't been looking in the right places. I'm going to be following this thread to see if anyone else uncovers anything.
But there were many contemporary people who left behind their thoughts on the expulsion. One of the most interesting (IMO) is Don Isaac Abarbanel, who was one of the leading Jewish financiers to Ferdinand and Isabella, who helped fund Columbus's expedition and who pleaded with the king and queen for the expulsion to be cancelled. Despite his having been extremely wealthy and influential in Spain, he left with all of the rest of the Jews (to whom he served as a communal leader) and moved from place to place in Italy for the rest of his life. While he didn't leave a memoir, he scattered references to his experiences throughout many of his Torah works (he's still considered one of the most important Torah commentators of all time). After the expulsion, his works seemed heavily influenced by his experiences and the despair in which they left him. He wrote a three-volume work on redemption and the Messianic era, as well as a Passover haggadah in which he contextualized his experiences with the experiences of the slaves in Egypt, hoping that in the future will come the redemption just as it came to the Jews then. If you'd like to read more about Abarbanel's experiences, they are discussed in his biography, Don Isaac Abravanel: Statesman and Philosopher by Benzion Netanyahu (Bibi's dad). If I remember correctly, Netanyahu compares some of Abarbanel's descriptions of the expulsion to his own knowledge of the Jews in the concentration camps.
There are other first-person reports relied upon by historians, including by Abraham Zacuto (a well-known astronomer and mapmaker whose work was used by explorers including Columbus and Vasco da Gama), Elijah Capsali, and Judah ibn Verga, but unless one reads rabbinic Hebrew and wants to dig up their relatively obscure works, they're not particularly accessible. They're also not necessarily accurate. One common feature in many of these works, for example, is the assertion that the expulsion happened on the ninth day of the Jewish month of Av, which is inaccurate (it happened several days earlier). This is significant because the ninth of Av is a traditional Jewish fast day and day of mourning for the destruction of the Temples, and it is a day with which many Jews then proceed to associate all tragedies which have occurred to the Jews over time. The statement that the expulsion occurred on the ninth of Av therefore is highly significant in terms of stating the gravity and cataclysm of the event, and is common among many of these accounts despite being inaccurate.
The bottom line, though, is that in any modern book about the Expulsion (such as the massive The Expulsion of the Jews of Spain by Haim Beinart) will be based on contemporary accounts, but with the necessarily historical context to let one know what the experiences of the expelled were like. Here, if you're looking for something you could read online, is a fascinating chapter from a sample of the book After Expulsion by Jonathan Ray, which includes excerpts from a first person account of one Shem Tov ibn Jamil.
I'll be following this thread to see what else others might suggest!