This is easy because in May you won't be able to do much at Crater Lake as most if not all of the rim road will be closed due to heavy snow. Crater Lake is also a very, very long drive from any of the other points you mention.

In May I'd actually minimize the time on the coast - maybe Ecola State Park and Cape Disappointment on the Washington side of the mouth of the Columbia River, and allocate the remainder of your time to the Columbia River Gorge, the Hood River Valley and Mount Hood.

The many waterfalls along the gorge walls will be full of water from melting mountain snow, the floor of the Hood River Valley will be full of orchards in bloom, and there will still be skiing and lots of vistas on the side of Mount Hood, accessed via Timberline Lodge.