First, if you are going to the beach or plan to be outdoors for most of your vacation, it is important to apply sunscreen to your whole body every couple hours even if you want to tan. If you do not, you could wind up getting badly burned and this may spoil your fun for the rest of the trip. It is also a good idea to wear sunglasses and a hat to help protect your eyes and your head from the sun. If you have really sensitive skin, you may want to get a sun screen with a higher SPF value for better protection.
As far as exercise, well on a vacation there are usually things to do that you cannot do at home, so use these activities for exercise while you enjoy them. If you are going to the beach, volleyball, Frisbee, running, walking, and even sit-ups and pushups may be a good work out choice. If you are going somewhere else, make a list of all the activities they have to offer and do as many of them as you can. Finally, if you really want a good gym workout, then go to the gym area at your hotel or ask for one in your area. This will help you stay fit and feeling good.
Being on a vacation does not mean that you still cannot eat right and get plenty of exercise. You just have to pick your choices carefully and remember to use the new location to your advantage. If you do this, you may find that not only can you really enjoy yourself but that you will really stay in shape as well. This will help you enjoy the whole experience for a long time into the future.