Based on the series I've done so far and the one I'm doing, this is how I'd order them, with my favourite first:
- Costa Rica 5K Training Series <-- In progress
- Parthenon Running Series
- Swiss Alps Summit Series
- Arizona Running Series
- Patagonia Running Series
If I was to do these series again, what order would I put them in, in order of easiest to hardest?:
- Swiss Alps Summit Series
- Patagonia Running Series
- Arizona Running Series
- Costa Rica 5K Training Series <-- In progress
- Parthenon Running Series
Series I've not done (alphabetical):
- 10K Training Series Part 1
- 10K Training Series Part 2
- ActivePulse Training Series
- Easter Island: Rapa Nui Running Series
- Grand Canyon Rim-to-River Trek
- Half Marathon Training Series, Part 2 - Japan
- Half Marathon Training Series, Part 1 - Bolivia
- Iberian Beginner Running Series
- Machu Picchu Peru Series
All series ordered from easiest to hardest (according to iFit):
- Iberian Beginner Running Series
- Swiss Alps Summit Series
- ActivePulse Training Series
- Machu Picchu Peru Series
- Costa Rica 5K Training Series <-- In Progress
- Grand Canyon Rim-to-River Trek
- 10K Training Series Part 1
- 10K Training Series Part 2
- Easter Island: Rapa Nui Running Series <-- Next Series
- Half Marathon Training Series, Part 1 - Bolivia
- Half Marathon Training Series, Part 2 - Japan
- Patagonia Running Series
- Parthenon Running Series
- Arizona Running Series
One thing I must say, these treadmill running series are no substitute for actually running in the real world. I find if I've only been running on a treadmill for weeks/months (maybe it's winter time and I've not fancied going outside), then it is really difficult to run outdoors and I'm really really slow.