Move over, Manhattan. A $1 billion mega-project in Orange County is set to transform an old military base into what could become one of the biggest urban parks in America — complete with lakes, museums, shopping, an amphitheater and enough space to dwarf New York’s Central Park. The sprawling 1,300-acre Great Park in Irvine is undergoing a massive overhaul that city leaders hope will turn the former Marine Corps Air Station El Toro into Southern California’s next major entertainment and tourism hub. Rendering of Great Park by Great Park Framework Plan storymaps.arcgis.com By 2029, the park is expected to surpass San Diego’s 1,200-acre Balboa Park in size and almost double the size of the Big Apple’s crown jewel of green space. Developers and city leaders have openly pitched the Great Park as a future West Coast counterpart to Central Park, except this version comes with amphitheaters, giant man-made lakes, retail villages and a sprawling complex.…