There are hard sweep spots; generally in the MK parking lot, MK entrance and mile 10.
BUT that does not mean that if you have fallen off the 16 minute pace you won’t get swept at any point. The ‘sweep clock’ does start once the last person crosses the line. You can assure that you are not in harm’s way by checking your pace at each and every mile. Do this through the use of a timer watch. By starting the timer as you cross the line you will have you own time at every mile point. So as you cross mile 1 you know you will need to be less than 16 minute; 32 minutes at mile 2, 48 at mile 3. Etc.
Now is the time to strengthen the legs. I would not focus just on the quads. Newbie runners tend to run on quads – kind of falling from step to step. There are strength run/walk workouts you can do as well as gym type work outs.
Running/Walking – Hills are the best way to develop a balanced leg muscle. First you need a hill. Ideally, you can find one with a 6-10% incline that would take at least 10 minutes to run up. (I use a treadmill). Warm up first then run up the hill. You want the effort to feel hard to very hard and your breathing to be just at the point where you may be able to say 1-2 words per breath and possibly the jaw has dropped open. Keep going up the hill at this intensity. Walk back to the start then repeat. Repeat 5 times. Note if you cannot make the top go as far as you can. Try to go that same distance on the repeats. Do this work out once a week. This works the hams and glutes; you may have a sore area just at the interface between these two muscle groups. It’s a good sore.
Squats –
http://exercise.about.com/od/exerciseworkouts/ss/howtosquat_2.htm These are great balanced leg workouts. Stand feet shoulder width apart and feet facing forward. Squat like you are setting into a chair. Your knees should remain in line with hips and ankles! Torso should remain upright and head facing forward. 3 sets of 15. Add weights once this becomes easy
Lunges -
http://exercise.about.com/od/lowerbodyworkouts/ss/lunges.htm - Follow this form. Straight back is critical as is keeping the forward knee behind the toes. 3 x 15 – add weights once it becomes easy. After than do a walking lunge where you move from one lunge to another – think exploding out of the lung position and into the next lunge.
Calf Lifts -
http://en.wikipedia.org/wiki/Calf_raises - look at the bottom example. Use a stair or step at the house.
I did a combo of walking/running the Princess last year as my first marathon event. I hope you have as much fun as I did. 
