I'm going to be at a conference in Vancouver, WA July 24-26. I've never fished the Columbia and was wondering what my options are for wetting a line then.

Can you plunk for salmon/steelhead anywhere near the Vancouver waterfront?

Any advice?

I've never plunked near Vancouver but I think anywhere you can access the river is a possibility if the water is moving. If you have a vehicle, drive downstream and plunk at Willows or County Line park or anywhere along the way. There are some good seams at the mouths of the small creeks along the way too (that you can plunk).

Rays coon striped shrimp with a spin-n-glow.

I hear people catch fish of wintler beach by who song and larrys, known to the fisherman as glass beach

Frenchman's Bar might be your best bet.
Definitely better "atmosphere" than down by Who Song's.
Steelies will be your target species in that time frame but ya never know when a nooker might come cruising by.

Thanks for the info!