Hope you enjoy WA section I of the PCT – it has great views of Mt. Rainier from the Chinook Pass part of the section, and pleasant forested country with lots of lakes and ponds heading N from White Pass.
To answer your question, I try to take my first backpack trip in April, snow conditions permitting, close to home in the rain shadow of the Olympic Mountains in Western WA. There’s a nice moderate 2 day loop (or long day hike) from Slab camp trailhead, along Upper Gray Wolf trail to Three Forks, then up to Deer park and Blue Mountain’s summit (great views), then down the Deer Ridge trail back to Slab camp:Â https://caltopo.com/m/06H5