I’ve just finished week 1 of the 8 week R-A program.

Josh’s 8-week advanced rock, I assume?

How tall should the box be?

Roughly 75% of the height of your knee.

Is a barbell an appropriate sub for dumbells/backpack?

Sure. Or a kettlebell held in a “goblet” position (in front of your chest). From what I’ve noticed, weight on the back creates more of a posterior load, while weight on the front adds more of a core load as well. I usually opt for the latter.

Is it better to go to harder types of dips (rings vs. bars) before adding weight?

Good question… I would think so. Harder exercises will likely recruit more muscle, especially stabilizers.

Are there any critical timings in the weekly schedule that can’t be tampered with slightly so long as it’s consistent (i.e. maintains the same recovery between strength sessions each week)?

So long as you’re recovered for key (anything technical, high-intensity, or strength-related) sessions, juggling your schedule is fine.

Alternatively if I do a “trail run” at 6am and climbing mileage at 7pm, resting the following day, does this seem to be obviously stupid or something I can feel out? This is mainly for the sake of maximizing chances to be outside, or having a climbing partner and avoiding the auto belay laps.

I’m not sure why this would be stupid… For fatigue, you mean. Same answer as previous question.

If trying to extend the plan 1-2 weeks for a later peak would you suggest a week to 1-4 or 5-8?

In general, it’s best to add more base weeks than sharpening weeks, so I would add them to the front of the plan rather than the end.