[AngelesCrestHighway]

I’ve seen Mount Adams from Mount Saint Helens also, but how the heck do you get over to it? Is it forest service roads only?

[cogitator]

Sorry, no idea. I just did Google maps and it sure looks like forest service roads are the only way there.

Confirmed. Climbing Mount Adams (source of the third image)

"Forest Service road 8040 to the Cold Springs campground". Apparently there's a ranger station at Trout Lake that has information.