Those days off may be used for total rest, stretching, or cross-training such as swimming or biking. If you are cross-training in another sport and are a beginning runner, it is definitely a good idea to have at least one complete day of rest each week. When 30 minutes of continuous running is reached, a person running a 10-minute mile will have covered a distance of three miles. As you progress into the latter stages of this schedule, you may want to increase the running to every other day, which would give you one extra day of running every two weeks. Days off allow the body to recover from the stress of this new exercise and prepare for the next workout.
Rest is very important, especially in the early stages of running.
Any training you do the day before is not going to help you during the race. It is better to go into a race well rested than over-trained and fatigued. When the race starts, go out at your regular pace. Concentrate on enjoying the event and finishing the race, as opposed to setting a time and being disappointed if you don't make your goal. Your goal is to have fun.