The Red Moon hangs some 3000 km directly above the Crater, which is about 800 km from the Quivin Mountains. If I were standing atop Quivin Mountain, the Red Moon would be visible to the left of the Eastern Rockwoods, almost half-way up the Sky Dome, which means it is visible almost everywhere in Dragon Pass, except in deep valleys or where obscured by nearby mountains. In Boldhome it is obscured by Darsh Peak.
Remember the Red Moon does not rise or set, nor does it move with the Sky Dome. It remains motionless in the sky, cycling between Red and Back every week.
You can see the moon even in the day. That’s been the case since the defeat of the Dara Happan rebellion in the 1st Wane. It is now much larger and brighter than when it first appeared, so large and bright that alone among heavenly bodies, it is visible all day while the Sun shines.
The Guide is definitive about the Red Moon. See page 648. We went over a LOT of variations while writing this up. That is a big part of the reasoning for the Guide – you can go to it for a lot of these questions. There is more on the Red Moon in the Lunar Mythology book, but it is built off the Guide.
What about its size relative to Yelm? From outside the Glowline, the Red Moon appears to be about the same size as the Sun. Within the Glowline, the Red Moon appears larger and closer to earth. The closer one gets to the Crater, the larger and the nearer the Red Moon appears. From atop the Crater Rim, the Red Moon appears near enough to leap to.
Could it eclipse Yelm if you viewed it from Thunder Delta? That eclipse effect might occur within the Heartlands in a few places, but only briefly. It would be within the Glowline so it might actually only occur within the Silver Shadow.