HT to botato for sharing two great mileage runs from the Pacific Northwest on FlyerTalk today. United is offering cheap fares to Boston and Philadelphia for around $230-240 round trip. And although I normally recommend routing through Houston for the most miles, in this case there is better availability through San Francisco. It only shaves a couple hundred off the total and even allows for same-day turns. (In particular, SFO seems to be the only option for mileage running to Philadelphia; fares jumped when I looked at going via Houston).
The first itinerary earns 6,765 miles and costs just $240. There is some variation in the fare, but availability is okay mid-week. You’ll pay 3.54 CPM, which is pretty good these days. Be aware that United is still operating at separate gates in Boston and the employees who operate the shuttle service didn’t seem to care at all about my tight connection the last time I passed through on a legitimate flight, not a mileage run.
The second option allows more time for turns and may also offer slightly better odds on an upgrade (but I think your chances are slim on either route, even as a Premier 1K). You’ll get only 6,400 miles at $232, or 3.63 CPM, and there is consistent availability on Tuesday/Wednesday. I’m inclined to pick Philadelphia because of the problems at Boston, but it’s great that both options can be achieved without the added expense of a hotel.