Sweet .if your going to Golden gate Park......go play Stafford Lake in Marin Co.....the course is in Novato Ca and it is the most Sweetest Course on the West Coast.....very Hard and has elevation changes with views of the lake lots of wildlife and just about every shot will test your skills here ......if your in the Golden Gate area bottom line please play Stafford Lake....skip Santa Cruz as it is a great course and one of the hometown favorites but you will have lots of golfers there and a wait is not uncommon....no wait at Stafford Lake and the most beautiful you will encounter on your adventure bar none......also Play Milo McIver in Oregon you can't go wrong there and just the nicest folks around too...hope this helps in your trip....have fun........play Stafford Lake!!!
Bill, er, William is right on with the WA recommendations. Just a couple things to add, if you're coming through Bellingham, there's a new course that's pretty sweet, still a little rough around the edges (some homemade baskets, dirt teepads, etc.), but is definitely a fun time. It's called Mossy Roc, in the Sudden Valley area. There's a new course in Sedro-Wooley, that I have yet to play, but have heard it's long and challenging. There's also Twin Rivers in Arlington, another fairly new course, but pretty well established and is pretty fun. I mention these three b/c they're all fairly close to I-5, easy to stop off and get a round in. Terrace Creek is also a quick hop off the highway, and it's my home course these days. It's one of the oldest courses in the Seattle area (maybe the oldest that's still around?). It's a good course, but as Bill mentioned, the best courses in the area are Lakewood, Seatac, and White River. Don't know what you're doing for accommodations on your trip, but White River has a campground right next to the course. Ft. Steilacoom is also worth seeing for sure. The local club there has done a good job of putting tee signs up so you can follow 3 or 4 of the most popular layouts more easily--still kinda tricky though, finding a local is your best bet.
And yeah, in OR, Milo is a must play. It's a bit of a drive away from I-5, but well worth the trip. Pier is also a sweet course, probably my favorite city course, just be sure to play it during the week or early on the weekends (it's a lot of people's favorite course). Trojan is a good stop along the way, it can be hard to navigate, but I was able to find my way around thanks to some arrows painted by the locals. Be sure to bring discs you don't mind losing though, most of the holes have water in play. Dabney is the other standout course I've played in the Portland area, but I couldn't play all of it b/c we ran out of light. Rooster isn't that bad of a course, I've certainly played far worse, but it isn't the best Portland's got to offer. Timber is, eh, so-so. Nothing bad about it, just nothing remarkable, it's like 10 minutes from Milo McIver though, so if you're in the area and have the motivation, you might as well hit it. I've only played it once, and it was after spending a day at Milo, it just felt blah in comparison.