The problem with taking vacations as Evil Overlord, is that no matter how well prepared you leave the office, some problem will arise fifteen minutes after you leave. Instead of remaining focus on regular duties, everyone focuses on this new issue. The odds are, had you remained in the office, you would have deemed the issue unimportant and nothing would have been done anyways. Instead you have the entire employed force working on a stupid issue and not accomplishing anything else. In the end, solving the one problem will only bring up thirty more problems, and that is what you will have to look forward to at the end of your vacation. No work done, and new disasters to have to take care of.
While away, someone will always need to be able to contact you, but if you are not careful, your vacation will quickly turn into not a vacation. If you truly cannot trust your underlings to think for themselves, and to obey orders, set aside no more than one hour each morning. At the end of the hour, cut all communication. You need to relax, you have too much on your shoulders, and if you do not relax, you are going to be wound up tighter than any politician working on a pet project.
It is true, when you return to the office, you will have a huge back log of emails, phone messages, and paper documents to go through, but if you planned accordingly, you will be just fine. If you cannot plan for, or anticipate this potential mess, you are better off not taking a vacation. In truth, you are better off not pursuing a career of Evil Overlord. You are a pansy, worse than the french, and should just turn back now.