Wish I'd seen your post sooner.
When I lived in Oregon City, I fished the Clackamas religiously. Although my focus was primarily Steelhead, there's a good run of "sea-run" cutthroat that would be fun on your 5 wt. Just up-stream from the Hwy 205 bridge, on the west bank, there's a cluster of submerged boulders -- cast around these in the evening and see what comes up.
If you get a heavier outfit sometime, there are Steelhead in the Clackamas literally year-around. A wonderful fly-drift is about 1/2 mile upstream from the 205 Bridge (river makes a sharp bend at the water intake station -- go about 1/4 mile upstream from there on the east band). This is an early morning, before the jet-sleds start pouring through thing. But I've caught a lot of nice fish there throughout the year, depending on water height and clarity.
The shad run should be going strong on the Willamette as of now. You'll need a sinking line to get down to them, but I've had reasonable luck from shore fishing beneath the 205 bridge. It's much better if you can get out in a boat -- just fish where you see the other boats upstream from Clackamette Park. Get your fly down deep and hold on. Should be a blast on a 5-wt.
Good luck. You'll find there's plenty of fishing within a few miles of home.
Last edited by Eric; 05-12-2014 at 08:22 PM.