If you have the motivation and time to do the full 18 week plan, I'd say go for it. But don't sweat the details too much if you decide to cut it down a bit....
Here is what I am doing and why:
I'm currently using the Hanson's method for the first time, for a half marathon. I'm actually following an adapted Beginner program similar to what I described above. Weeks 18-13 out are easy base milage averaging 35 MPW, which is more than is prescribed in their beginner plan. Weeks 15, 14, and 13 I threw in a Tempo run of 2 miles at race pace (5 miles total run) just to get my legs moving a bit.
The main reason I'm only going to do 12 weeks of "real" hansons training is for fear of injury. Stress fractures are not my friend, i'm hoping that the shortened phase that includes speed workouts will be successful in staying injury free.
Don't take my words as the bible, I'm more of a hobby jogger these days that will never come close to my College PRs again. I am shooting for a PR in the half marathon distance, but I admit it is a pretty slow time to what I am probably capable of if I trained all out.
I really like the hansons plan so far as it has kept me extremely motivated and excited for each run. Each run has a purpose, and I've managed to take my easy days EASY for the first time in my life. I think the easy days have improved my overall endurance strength greatly.