Responding to Wild Will...sure, adjust SC or any other program to whatever suits you best. SC has options for people who can't run many days a week, but you can also change an easy run day to cross training if that works best for you. Here's a thought: The smartest SC user will be the one who takes the parts of SC he likes, and makes adjustments on the other parts. As long as you don't start overtraining.
With regard to weight and marathoning, there's no doubt that it's an advantage to being smaller and lighter. Just look at the Kenyans and Ethiopians and Japanese. But Paula's not short, and some big, strong runners are very fast. Again, the only thing any of us can do is to be the best we can be, and make the sport work for us--keep us healthy and fit.
That might bring a gold medal to some. But for most of us, it's about personal challenge, satisfaction, and good health.