Are you an experienced marathoner? Going from 1 hour runs to a 3.5+/- hour run in 5.5 weeks without risk of injury sounds pretty agressive to me based on what I've read, particularly if you are already injury prone.
Have you done a foot evaluation to make sure you are wearing the right style shoe for your foot geometry and gait style? The above book takes you through all of that stuff.
You may want to consider wearing a set of night splints to make sure your achilles and fascia stay stretched out over night and do not stiffen up. A lot of runners squeak by with this method.
Good luck and let us know what happens.