Breitenbush isn't close, but the hot spring might make up for that.
You might want to consider Oxbow Park, on the Sandy River just east of Gresham. A steep climb out, though.
And Milo McGiver State Park near Estacada might be something to consider. I've never been there, but Cycle Wild
does camping trips there. They have a trip planned for Stub Stewart in a couple of weeks, if you're still considering that.
Champoeg State Park is also relatively close, west of Wilsonville on the south side of the Willamette. Jonathan did a story
on his camping trip there over the July 4th weekend.
And there are some campgrounds in the Gorge that aren't too far.