Oregon Coast Whale Watching can be done all year round but during the late spring through fall the whales are a bit less. So it's best to catch the most around December through May. Don't get me wrong you can still view them but it'd be like 6 or so whales as opposed to 30 or so.
As for traveling to the nearby states, it depends on what you're looking to do. A
day trip to Seattle might be worth one of those long weekends. You can always plan a trip to
California. Personally, if I lived in Oregon, I'd do some trips to the neighboring states.