As far as English sources go, there are a couple of options.

The Penguin edition of Columbus' four voyages to the New World is still a good starting place - The Four Voyages, edited by Cohen.

There is a newer edition with a better critical apparatus for the 1492-1493 voyage in English - The Diario of Christopher Columbus’s First Voyage to America, edited by Dunn and Kelley.

The best general biography of Columbus is still S. E. Morrison's two volume Admiral of the Ocean Sea, and Morrison also edited a collection of Columbian documents - Journals and Other Documents on the Life and Voyages of Christopher Columbus.

No matter which source you read, you are still working with extracts from the writings of Bartolomé de Las Casas. Las Casas (it is believed) had access to Columbus' journal of his first voyage, and included extensive extracts in his work Historia de las Indias, published in 5 volumes in 1875 & 1876. (Volume 1, Volume 2, Volume 3, Volume 4, Volume 5)

Finally, the most recent work on the intellectual world of Columbus, is Wey Gómez, Tropics of Empire. Wey Gómez takes Columbus seriously and thoroughly investigates and explains why Columbus thought he could sail West (and importantly, South) and arrive in China/India. It really helps someone with modern sensibilities understand medieval geography and astronomy in a way that most works (for popular or modern audiences) give short shrift.