Thanks for putting this up. I’ll do my best to answer your questions.
1) Each week has 3 main aerobic workouts called “Run/Hike”, “Aerobic Threshold Run/Hike” and “Hike on hilly terrain” – Should I be aiming for any difference in intensity between these workouts? Is it ok to push into Z2 in one of them?
These are all meant to be in the basic aerobic metabolic realm, so Z1-2 range. The intensity can be in the Z1 range for he longer workouts and get up into Z2 on the shorter ones or on the uphills on hillier workouts. If you have a high basic aerobic capacity (AeT) then you will need to do most of this base training in Z1 (Z2 will be too hard for a high % of the base training). If your AeT is low then pushing into Z2 more will be helpful and speed the aerobic development.
2) For the “Hike on hilly terrain” should I carry any weight? If not and I have the choice between running / hiking, is it preferable to run? When hiking my heart rate is typically well below AeT except on the uphills, whereas running I can hold a higher heart rate downhill.
If you are in the Transition Period or early Base Period weeks then don’t carry weight. Or at least not much more that you need to an extended hike such as water. As the plan progresses there will weight uphill hikes designated as such. If you can stay in Z1-2 then running is going to give you more bang for the time spent. So run the flats and hike the hills. That’s what we mean when we say run/hike.
3) lastly my local hill is only around 150m high, it has lots of terrain though and a typical 1.5 hour run will include 750m of up and down. Is this “Hilly” enough? 1.5 hours is about the most boredom will allow on this hill although it does seem to involve more elevation my other option
Yes, this is hilly enough.
Alternatively nearby are bigger hills which I can access at weekends suitable for up to 4-5 hour runs. here a 3 hour run/hike gets around 1300m up and down. Is this suitable for the sunday “Hike on hilly terrain”?
Yes this sounds like a great place to do these workouts.
For any of the “Steep uphill hike” later in the program should i do laps on my hills, or suck it up on a stairmaster?
Real hills always beat a stair machine. You’ll want as steep a hill as you can find though for these. 10-15% minimum grade. 20+% is better.