I'm sure you will be totally fine and have a fantastic vacation. However, I know how once you get something in your mind, it's hard to let go. If you don't think you'll be able to sleep at night thinking someone is going to come in, here is a simple thing you can do. Bring a small set of windchimes (I'm talking those small cheap ones you can get at the drug store) and hang them on the doorknob. If the door moves, you'll wake up to the windchimes. If there is a sliding glass door you're worried about, bring a suction cup and hang some windchimes on the slider with the suction cup. If the door slides open, you'll hear the chimes. I doubt you'll need it but if it will make you sleep better at night, what do you have to lose right.