I snagged the remainders of OR 38, 36 and 200 a few days ago, 100% completing the Willamette Valley routes. 200, of course, is still unsigned.
This leaves 42S, 241, 255, and 542 for the Coastal routes, 66, 99 (south of Yoncalla), 138 (east of Roseburg), 140 (west of White City), 227, 229, 234, and 273 for the Rogue Valley/Southern Cascades routes.
Next trip will be finishing off US 26, picking up OR 380, 27, 370, 361, portions of US 97 and all of 197.