My first question is whether it is appropriate to begin these ME sessions with say six reps of hill bounding followed by the long ME reps? Allowing me to maintain that anaerobic and strength capacity.
Do you mean combining the bounding into the ME session? I don’t think you’ll need to.
The long, heavy ME carries are what we normally prescribe for mountaineers in their specific phase. For skimo and trail running, that cadence is too slow and the periodization is not ideal. Instead, we use our gym-based ME protocol and schedule it early in the macrocycle. It’ll be perfect timing if you add the Runner ME right after your hill-bounding series.
My second question is whether there is a need for Z4 reps given the length of my goal? Many of the uphills are steep and will be power hiked, so I am wondering whether to just continue with ME reps.
Instead, progress the Z4 into longer intervals of Zone 3. This “inverted intensity” (Sprints -> ME -> Z4 -> Z3) approach can work really well but you have to be careful. You must maintain your easy volume throughout. If you don’t then the high-intensity will erode your base and make you slower rather than faster.
Also, if the race is steep then the training should be steep. Rather than do fast running Z3 & 4, do the intensity in steep terrain as Z3 & 4 speed-hiking.
Lastly, 9,000m is a lot. You’ll need to strengthen your legs for the descents. Make sure that’s part of your plan. A progressive series of short descents with some speed is a good approach, but again, don’t over-do it. The eccentric loading when going downhill can really trash your thighs.