If there's any leeway in your training plan, try to schedule key workouts and long runs before or after your trip. For example, if you're training for a marathon, aim to complete your 20-miler the week before you leave, and then plan for a shorter long run—maybe 10 miles—while you're away. Every training cycle should include lower volume and intensity weeks, so if you can schedule those during your vacation, you will be less stressed. That's what vacation is all about, right?