Create a comprehensive weekly gym program tailored for a 40-year-old man. The program should encompass strength training, cardiovascular workouts, and flexibility exercises. Include specific details about daily exercise routines, including sets, reps, and intended duration for each workout. Additionally, provide recommendations for warm-up and cool-down stretches, as well as rest days or lighter activity suggestions to optimize recovery. Ensure the plan is suitable for someone at an intermediate fitness level, and offer modifications for common exercises to accommodate any potential limitations.