Complex sentence: After the war, some came back to develop the ski resort established by Walter Paepcke, Container Corporation of America president who with his wife Elizabeth had found Aspen an ideal place to establish a music festival, and invested heavily in rebuilding the city.
Split into simpler sentences: After the war, some came back to develop the ski resort established by Walter Paepcke, the president of the Container Corporation of America. He and his wife Elizabeth had found Aspen an ideal place to establish a music festival, and invested heavily in rebuilding the city.