Travel is where most people's discipline falls apart. Different bed, no gym, all-inclusive everything. I get it, and I still don't let it slide.
The trick is lowering the bar, not dropping it. A hotel room and twenty minutes is enough to keep the habit alive. Bodyweight, a run, whatever the place gives me. Something beats nothing every time.
I still eat well, still move, still sleep like it matters, because it does. A week off the rails costs more than the week itself.
Discipline isn't about being perfect on the road. It's about not needing motivation to keep the basics going. That's the whole game.