I like to try out different training plans. The one I used focuses on speed, then efficiency, and you can adjust your mileage/cross-training to suit your needs. If you are interested in getting a copy I can send it to you. I'm a low mileage person (25-35 mi) who likes to cross-train. For me, this keeps me from injuring my legs, but do what is right for you. Before the marathon training, I had been doing short races and a lot of speed workouts in winter/spring, so I thought this would be perfect for me. All my runs except for track workouts had some hills in them. You can never get enough hill training!
Now SFM is over, I'm going to take a week off, SWIM, then 6 weeks of usual running focusing on hills and strength, then another 12 weeks to get ready for CIM. They have several training plans on their website. A little strength training goes a long way! For the first time at SFM this year, I felt like I was using my whole body to get up the hills: from my legs, glutes, core, and arms. At the end of the race my arms were actually sore from sprinting to the finish.
As you can see, my whole year is planned around RUNNING!