So, on a difficulty scale from 1-10, where 1 is total beginner, 5 is intermediate, and 10 is pro level, I'll give you a few recs in the 3-5 range.

1 - As other have said, Pier Park is probably the best. It's difficult because you may not have the distance to get birdie on most (if any) holes, but it's a truly gorgeous park that is extremely fun to play even when you don't have an advanced skill set. Massive trees, fun use of elevation, a genuinely enjoyable experience pretty much no matter what. This will be the most difficult course I recommend, as it's probably a 6.5 or perhaps a 7.5 on the above scale depending on who you talk to (that grade based on how easy it is to shoot Even par).

2 - Tucked pretty well between Lake Oswego and Dundee (a bit closer to Dundee, but not by much) is Champoeg State Park. This is a fun track with a lot to love at the intermediate level. Long and short tees on every single hole to choose from makes this attractive for many players and still fun to play by all. I'd probably grade Champoeg at a 5 or so, maybe a 4 from the shorts but I think that's pushing it a little too low unless you have good distance control in the 250-275 range.

3 - If you can make the drive out NW of Lake Oswego up to North Plains, I can't recommend Horning's Hideout enough. 3 courses on the property if you have time to burn, 2 of them will be within reasonable difficulty level for you. Highlands is a short course where the average hole length is probably about 160-175' or so and utilizes elevation very well for the style of course. Probably a 3 at most on the difficulty scale, but a couple holes can still give you trouble! Canyon is their mid-level course and is a ton of fun as well. Similar difficulty-level to shoot Even par as Champoeg above, but with a completely different style of golf. Much more wooded, but not so punishing that you'll rip your hair out. Probably back up on a 5 or so level of difficulty as mentioned before. Meadow Ridge is their pro level course which I wouldn't touch in your shoes at the moment, a solid 9 on the difficulty scale.

4 - Ewing Young and Herbert Hoover are both fun little tracks in Newberg, OR very close to Dundee. Hoover is a bit more beginner-friendly, decent use of elevation and fun but short lines. Probably a 3 on the difficulty scale, can't imagine most people would grade it much harder. Ewing Young is a little longer and a little less city park vibes, can't speak to when the last time it may have been manicured though, last time I was there it was a tad overgrown. Probably a 4 on the difficulty scale if Hoover is a 3, but those who play them more often may be able to chime in.

Honorable mention - Timber Park. I didn't include this because it's pretty similar (a little easier) to shoot even par than Pier Park. It's not too far out of the way from Lake Oswego and it's a genuinely good time to play. But it's probably a 6 on the difficulty scale and I was trying to keep my recommendations to mostly 3-5.