Comment by cyrus_

You can walk into the office, but you won't get a meeting with Wyden if you aren't on the schedule. Instead, if you are a resident of the state, they'll have staff that will meet with you in a small conference room, take notes, maybe ask a few questions. These are typically fairly young intern types, so don't expect too much depth from them (in my experience, you're going to get some very naive questions if you bring up anything related to science/tech policy). They'll then tell you that you are being heard, thank you, and send you on your way. This is occasionally a useful thing to do, e.g. to bring attention to a niche issue, cause, or special interest that their office might not be aware of at all.