How far did networks of Jewish merchants go in medieval times?

the following was an april fool's joke. Jews in mesoamerica don't real

Great question! The Jewish community of India is somewhat well-known as far afield Jewish communities go, forming the edge of the "Jewish universe" in the minds of more centrally located communities. However, that's not the limit of how far Jewish merchants would travel.

In the 12th century, a number of merchants began sailing around the Pacific, trading between various islands. The distances were great, but by stopping at every available island trading was easily accomplished. All sorts of basic goods were traded--beads, textiles, metalwork, etc. Even plants and animals were exchanged. But since the distances were so great and the populations so small, these merchants were constantly searching for a more lucrative trade route.

In 1284, they found it. A ship, tossed by a massive storm, landed on the modern-day coast of Mexico. Finding a large society with substantialy population (and therefore good trading opportunities), the Jewish merchants permanently settled in Mesoamerica. They established a culture with a unique blend of Jewish and Mesoamerican elements, and plied trade routes in Mesoamerica, based out of a handful of small Jewish-majority city-states. The prolific nature of their trading is attested in artefacts, with Jewish ritual objects, including one Torah scroll, found as far north as British Columbia. But most of the trade network was based in Mesoamerica.

This may, however, not be exactly what you're looking for. Because of the draw of Mesoamerica, the Jewish Pacific trade network essentially ended, with all the merchants and their families migrating east to the Americas. The Mesoamerican Jewish community's network of merchants was, for all intents and purposes, entirely severed from the wider network of Jewish merchants and traders.

The source on this, by the way, is a work of scholarship in Yiddish written in the 1980s, called יידן פון דער ים-פעסיפיק און מעסו-אמעריקע: א גוטר שקר "Jews of the Pacific and Meso-America--a Thorough Analysis", by Dr. Michael Charles Patish.