There were moderate size browns in the Little Deschutes back in '93-94. I've been meaning to go back there some year...
There used to be brook trout in the pond at Keeps Mill (eastern Mt. Hood Forest, where Clear Creek joins the White River), but since they aren't native and ODFW doesn't want them there, they've probably been fished out by now. The two or three I caught were small, back in the day of 6" limits, and I don't recall seeing any over 8".
Brook trout in almost every high lake in the cascades, lots in the high elevation streams in the cascades as well, probably the most common trout up there. Browns in SW Oregon are not to common but there are some in the North Umpqua above Soda springs res., Tokatee res., and lemolo lake. Central Oregon is probably your best bet for catching brown trout.
All the lakes past about Steamboat area up the Umpqua have brooks in them. Lots of browns in the Tokatee system and all the forebays. Tokatee is my favorite spot I would think its close and there is lots of different pieces of water to cover with the forebays and what not.
I know a few years ago, I got a nice 4 1/2 pounder out of East Lake. I have caught several nice ones out of Wickiup. Not as big, But Wickiup has some mosters in it, I just haven't caught one. I was in the Kokanee hole in Wickiup 3 years ago and every other fish we caught was a 14-16" brown. Just a perfect eating size. We only keep 1 meals worth and C&R after that. Hopefully that will make it possible to keep catching them. In Wickiup I was using the Worm, Crawdad tail, and red egg cocktail to catch them. About 3 feet off the bottom. At East Lake we trolled a F-4 Flatfish in frog pattern. Good luck, If nothing else it is beautiful up there and you can have a clear head for a few days and not think about work. Qwa