It's hard to develop a good habit. It takes me a lot of list writing, a lot of alarm setting, and a lot of calendar appointments to make a habit stick. But, once it's there, I lock it in. And I adhere to it. Exercise is like that for me now. Of course, it's my job, but when I have a disruption in my work schedule, the fact that fitness is my career just adds pressure.
The biggest disruption to my training is travel. Which stinks because traveling is the best. But what we (all of us workout people) is that, even if we have a specific workout/class/program that we intensely follow, all movement works. Taking a walk works. Doing pushups on your motel floor works. Hiking works. Taking a new class in a new place works. We, as humans, just hate change. But rather than getting hung up on missing your routine, use a disruption as an opportunity to explore other things. Think of your vacation as a fitness vacation--not because you stop training, but because you explore something different. One of the best things about training is that there are some many ways to move: dancing, lifting, running, climbing, jumping, skating... And besides, it's usually uncomfortable and constricting when you try and maintain an exact program in a different setting.
Personally, when I get disrupted, I find it more interesting to keep the theme of the habit--fitness in this case--but explore within that category. Not everything has be about habit maintenance; it can be about habit expansion. And the ability to flow and change leads to a softer approach to life. It leads to less stress and pressure. Don't lose the habit, but allow it have variety.