Complex sentence: The next big champion of the central route was Theodore Judah, who undertook to survey and plan a way through what was one of the chief obstacles of a central route to California: a way over the high and rugged Sierra Nevada mountains.
Split into simpler sentences: The next big champion of the central route was Theodore Judah. Judah undertook to survey and plan a way through what was one of the chief obstacles of a central route to California: a way over the high and rugged Sierra Nevada mountains.