The expression "Detailed plan of a journey" is best replaced by: Itinerary

Here's why:

• Passport: A passport is a document required for international travel, not a plan for the journey itself.
• Travelogue: A travelogue is a written account of a journey, not a plan for one.
• Itinerary: This word specifically refers to a detailed plan of a journey, outlining the route, stops, schedules, and activities. It encompasses all aspects of the trip, making it the closest match to the desired expression.
• Timetable: While a timetable specifies times and schedules, it may not include all the details of a journey plan like routes, stops, or activities. It's a smaller component within a comprehensive itinerary.