I haven’t coached any active mountain guides, but our head coach, Scott Johnston, has. From what I’ve heard from him, it’s tough to juggle the impact of guiding with more event-specific training.
As you’ve described, a big issue is that guiding is long, tiring, and wears on the body. I think 3:1 rides are a good idea. In addition, if possible, I would include some longer runs when you know you’re recovered from your guiding days.
I hope that helps.