I am guessing that I will be speaking largely to deaf ears, but from my experience (4 years of high school, 4 years of college and two years post-collegiate) rather than setting a standard of trying to hit a certain mileage, you are much better off just running, not worrying about time or distance till after the run and see where you are.
From what I can tell you are stretching to hit 100 more because it is 100 than because it will necessarily really help your training.
To put it in perspective, I ran 16:28 in High School and 9:53 in the two mile. Over the summer I averaged 60 miles a week, all easy runs, all singles. I was running mid 26s in college and in my first indoor meet ran 15:42 for the 5K. I enjoyed running, ran how I felt (some days were much faster than others, but non were scheduled workouts) and was happy to see I was running more than ever before. The results were dramatic.
Since then I have found that especially when I am building up a base, doubles--especially equal doubles--don't really help my training much. The benefits of a continuous 15 mile run are very different and far greater than a 7.5 mile run. The only time I did doubles was when I did workouts and I kept them short (4-6), easy and made sure to get a good stretch in after.
The only time I ever ran 2 hours a day consistently it was all on trails and I would not recommend it on pavement.
For you, my advice would be to run 8-11 a day and see how you feel. It will be easier and, in my opinion, better for you to simply do singles but make them a reasonable distance or time (hour to an hour and half). Your mileage should be 60-80 depending on how fast you run. Running shouldn't feel like a chore.
Those are my two-cents, take them for what they are worth.