As my wife can tell you in more convincing terms than I, my snoring was a real problem to the point I would often wake myself up from the sound. I got one of the mouthpieces (Puresleep) and it works terrific. I don't snore at all any more and even I wake up feeling more well rested.
In my experience, the first month of using the mouthpiece was difficult. The way it works is that it pulls the lower jaw slightly forward to open up the airway a sufficient amount to prevent the epiglotis from vibrating. Unfortunately, the jaw muscles don't react well to being pulled out of place like that, and for the first month, until the muscles adjust, the first few hours of each day my jaw muscles were in quite a bit of pain whenever I openned my mouth (imagine the sensation of a cramp every time you openned your mouth for the first 2-3 hours each day and you've got it). Also, it resulted in my have a slight underbite, again only for the first few hours each day until my jaw settled back into its natural position.
Over the course of that first month, my jaw muscles got accustomed to the new position and the pain eventually went away. I've been using the mouthpiece for 13 months now and wake up without any pain or discomfort and eat breakfast with a normal overbite. If you are going to use a mouthpiece to deal with snoring, I definitely would recommend doing it well in advance of your vacation. It would not be pleasant to have to deal with the jaw discomfort that first month on vacation.