Because I'm working it out for myself, might as well share.
Stepping stone - 5 min brisk walk, 10mins at 150bpm, 15mins at 155bpm, 5mins at 160bpm, 5min brisk walk (30min total run)
Stamina - 5min brisk walk, 10mins at 158bpm, 20mins at 160bpm, 5mins at 165bpm, 5mins brisk walk (35min total run)
Speed - 5min brisk walk, 5min at 155bpm, 1min at 165bpm followed by 1min at 150bpm (x6), 5min brisk walk
They don't look too bad if you write them out like that...