I'm looking to use the Maffetone Method for my basebuilding phase of marathon training. I would like to be able to build up to 50-60 mpw comfortably within the next few months. I'm aiming for a fall marathon, so I would likely start a 18-week training program in July. I currently run about 25-30 mpw right now. Can you recommend a basebuilding program for me? A lot of what I've seen out there includes some form of speedwork.