In general terms, gifted education in Oregon is an unfunded mandate. They are obliged under state law to identify such children and offer them appropriate differentiation, but-- the devil is in the details, as is probably obvious to anyone reading. Let's just say that I've been severely underwhelmed by every example of such "appropriate differentation" that I've seen or heard about from another person with first-hand knowledge over the past ten years or so.
There are some extremely fine private schools in the Portland Metro area-- Catlin-Gabel comes to mind immediately. There is also an IB magnet school out in the western 'burbs. Lake Oswego has the best reputation (mostly) and Gresham-Barlow among the worst.
As usual, though-- it boils down to a more granular look at individual schools and even further, to individual classroom practices. The state has also got both K12 and Connections as virtual schooling options if you go that route to credentialing, and dual enrollment practices are robust during the high school years-- and that is true at almost any high school in the entire state.
PDX schools will be partnered up with PCC or MHCC for dual enrollment credits. They transfer seamlessly to any public uni within the state, by the way. I know several students who earned a year or more of college credits that way while in high school-- and while rates vary somewhat, it is a BARGAIN. We paid just $25 for fifteen quarter credits during DD's last year in high school. Yes, $25. Not a typo.