Do you absolutely need to live in a big city? What is your occupation?
Eugene, for example, is very different than Portland, with very different positive and negative aspects.
It is a smaller city, with far less overall traffic. But, also a less vibrant night life (at least away from the University).
We do have a good airport, but I don't know how one gets there without a car. Perhaps a bus. Or using a locally made Bike Friday bicycle
A lot of flights will puddle jump from Eugene to Portland, Seattle, Denver, SF, or Salt Lake and transfer.
There is an Amtrak station.
For me, Eugene is the "Big City"... and Portland is gargantuan (still small by US standards).
Being a small city, there are also rural suburbs. So, one can be out in the boonies, and 1/2 hour by bike in the middle of the city.