Washington State. I'm going there.

I have twelve days and plan on doing a fair bit of driving, but would also like to do a few one-to-three night backpacking trips. Plus Mt St Helens.

Could any WA folks give me tips on good places to hit up. In particular I'm looking for ideas in North Cascades NP and Glacier.

Notes:
* June 6 - 15
* Going to be solo
* Moderate physical condition; pretty out of shape right now, but not fat or a bitch
* More or less expert level backpacker (have done all of NH section of Appalachian Trail, chunks of Colorado trail, and have ultralight gear.

Questions:
* Good moderate, possibly strenuous routes to remote, quiet campsites
* Do I need my snow spikes in early June out there?
* Is a bear canister necessary? I keep a clean as fuck camp and am good on bear control, but is there a major issue out there?
* I'm guessing it is not hard to find (filterable) water sources out there. Am I right?

Mostly, I need

Looking forward to hearing your thoughts.