Instead, I chose to do some stair running (30 reps of the building again) followed by some strength moves (i.e. squats, push-ups etc, nothing too fancy). I was harnessing my inner Rocky, and it was intense hey! Here's a sweaty, tired snap of me on the stairs in question:
So, I know these stairs aren't exactly the terrain I'll be running on, but I hope they'll prepare me somewhat for some of the uneven surfaces and up and down sections (which, I'm pretty sure form the majority of the trail race).