Oregon
Hi, I live in Portland and have been surfing the Oregon coast for about 16 years. I only go out about 10-14 days a year now, since I do so many other things like bouldering, mtn biking, kayaking, windsurfing, cross country skiing, etc.
I have met some Cali surfers who make the trip up north looking for waves. Most of the time, they get in and get wet, but do not do much in the way of any kind of good surfing due to inconsistant conditions.
I obviously can't tell you where the best spots are, but I can tell you this...
The only way a Cali surfer would get any value out of an Oregon surf trip would be to combine it with some other agenda.
Such as mountain biking in Oakridge Oregon or Bend and then heading over to the coast. Also, lots of really great bouldering in central Oregon. Sport climbing too, but roped climbing is tougher to coordinate with a partner, more gear to bring, kids get bored, etc.
Or a souther Oregon adventure: go on a guided 'rubber ducky' white water trip (class 2) on the Rogue R. by Grants Pass (the day section - warm water in summer) and then take a windsurfing lesson at Floras Lake (flat water sailing only separated from the beach by a dune) and then find some wind protected surf in the Port Orford area (or further south). Lots of dry summer heat and warm water swimming in the Medford area. Crescent City not to far from there either.
A winter ski & surf trip is o-u-t. But hey, you can do a Spring ski & surf trip. Do that in early April and just hope for the best. You need to find a bit of a cove or headland or jetty type of protection from the slop. (Wind can blow from any direction that time of season)
Check ski areas for operating times & dates. There still is snow, but they start cutting back on open days. This is a great way to hit the snowboard parks in nice weather. Also, I have hit powder days this time of year too - it all just depends on the weather. April on the water can be pretty good or stormy, but you have many more good days than March.
However, I can't recommend just taking an Oregon surf trip where your days are numbered and you are expecting to score descent rides. Better to make it an adventure and soak it all in.
Final note: we surfers in the northwest have local knowledge of when the spots will be good. It depends on swell direction, time of year, what the sand on the bottom is doing, tide, windswell vs groundswell, chop on the outer waters, etc, etc, etc. An experienced surfer can predict a clean day at a given spot, but it takes a local surfer to predict when the waves are going to peel and not just close out.
It is very hard for a visitor to pick a spot on any given day - even harder to plan a good surf trip. The experienced go out when conditions dictate. The beginners just go when they get a day off - and sometimes get into serious trouble with currents.
Last bit of advice: everyone says it is better in the fall. But medium sized fall surf ends quickly and big closeouts come early - even when the weather is still nice. Needless to say, it can be tough to get out past the soup. And we are much closer to Alaska, so the period is always shorter. Lots of fall surf vacations are spent by paddling until arms are burning and then sitting on the beach. Not fun.
I take my surfing vacations in California, so I hope I gave some good advice without being too encouraging or discouraging. I am considering moving to the Stockton area in the future, so I might see you out on the water some time in the next few years as I check out the area.