I’ve used the Runners World 16 week, 4h Marathon training plan to put the plan below together. I was able to download the entire plan to my Garmin Forerunner 405cx using the target training paces as a guide. So all I need to do to stick to the plan is check what’s on the agenda for the day, pick the training setting on the watch and off I go. The watch will then track my distance, tell me when to switch from slower warm up sessions to speed sessions, and make sure I run in at the proper pace. The beeping noises take a bit to get used to, but after a while you don’t even need to look at the watch anymore.