1. Know where the nearest emergency medical facility is.
2. Ensure your cell phone works wherever you are. If not some type of extra radio might work-CB, ham (assuming some work on different frequencies/principals).
3. Know your EXACT location by using GPS coordinates.
4. If you can't get emergency help it is essential you have a second person that can drive.
5. Take any meds, etc., that you may need with you.
6. Use precautionary measures prior and during your vacation-watch your diet, activity or other such potential cause of an issue.
7. Have all your medical info written down-chronic conditions, allergies (medicines especially), insurance info, doctor's name & number, etc. These things aren't easy to remember when one is stressed.