This is a very helpful post. I'm orignally from the East Coast as well and have been enjoying hiking the taller mountains in the gorge and coast range but am looking to get into mountaineering.
I've purchased my St. Helens permit for July but am thinking I might make a trip up earlier than that. Definitely sounds like it's more fun in the snow. Glissading is a fairly new concept to me and it sounds awesome... like big kid sledding.
Sounds like Helens is the most tame you can get near Portland. Snowshoes at most right now....
What about avalanches? Where do I learn more about those, when they occur, and avalanche safety reports? Would those even be a real issue right now?
Just like Mark, I have no glacier experience and the Cascades are far larger than anything back east.