Portland can be really, really bad about car rent costs in the summer but can be reasonable at other times. I think there are also brewery tours there if that's your thing.
Here's a pic of the falls u seek that I did in May some years ago. There's also a trail that goes under the falls.
National parks and public transportation don't tend to mix too well in the U.S. Remoteness usually comes with the package. Though in Alaska you have a good number of people getting to Denali by bus or train (though often with cruises) and then the tours inside the park are by bus.