stick to the plan
Those who stick to the plan generally reap the rewards.
Your body doesn't care about the holidays. Missed training is missed training.
Your body doesn't care that you are out of town. Bad nutrition is just bad nutrition.
Your body doesn't care that you are "so busy". Lack of sleep and recovery makes you LESS productive while you are awake.
If you make the time to train during the holidays, you'll keep up your muscle mass as well as keep away the fat.
If you have the discipline to be consistent with your nutrition, your immune system will keep up and you'll provide your body with what it needs to get through the holiday season.
If you set aside the time to sleep, you'll be MORE productive the hours you are awake and have more energy to train, work and get things done.
If you consistently do the right things, you'll be rewarded with more of the things you want.
Even during the holidays. Find the time, get the good things.