Complex sentence: He disembarked at Buenos Aires, supposedly to travel to Valparaiso overland and rejoin his advisers who were continuing by sea, but after waiting two months in Buenos Aires he caught a ship home.
Split into simpler sentences: He disembarked at Buenos Aires, ostensibly to travel to Valparaiso overland and there rejoin his advisers who were continuing by sea. After waiting two months in Buenos Aires he caught a ship home.