The hardest part of any form of exercise is simply just starting it. One way to make it easier is to lock in a time of the day and stick to it. So find whether your resort has a gym or some classes, or go check out where there is a nice, safe jogging route and just do it.
I like to work out early morning, when my motivation and energy levels are high. For yoga practices, the hour before dawn (known as ojas) is a very spiritual time when it is believed the atmosphere is charged with powerful electromagnetic vibrations. This can make for a very uplifting experience.