The primary thing that I keep consistent is making sure I'm eating every 2-3 hours. I absolutely despise feeling "hungry", I feel like my stomach is digesting my internal organs or something.
Either way, things stay pretty structured on their own in regards to nutrition once you have a system down. I eat basically the same things at the same times each day, but my primary concern is consuming enough calories to not only maintain 265 lbs. of body weight, but hope to gain additional mass beyond that.
If I were to spend a weekend away, and eat a normal 3 meals in a day like the ordinary folk, I would lose about 4-5 pounds over that weekend. (It has happened several times)
Training is very consistent based on the fact that I always workout at the same time each day (after work), and in the same location. However, methods of training are a different story.
Also, I noticed you applied the word "counterproductive" to skipping workouts once in a while, cheat meals, etc. These things are only counterproductive if they begin to happen more than "once in a while". If you're feeling run-down, skipping a workout isn't going to kill you, and it will probably help. Likewise, a "cheat meal" now and then won't do much harm either, especially if you're trying to gain muscle size. I would be more concerned that you're not eating enough, before I'd be concerned about you "cheating" on your diet once in a while.
Like I said, this stuff doesn't have to consume your daily life. Just take the time to learn how to eat, lift and rest properly, and it will just become a part of your life that you enjoy, not a hassle to try to juggle around and worry about.