Just north of the little town of Plush, OR, is Hart Bar, a small interpretive site at the southern end of the Warner Wetlands Area of Critical Environmental Concern (Birding Oregon p. 21). A short trail leads through the marsh, providing views of shorebirds and waterfowl. The parking area has a primitive toilet and several interpretive signs. On the day of my recent visit, the wind was quite strong, making it difficult to hold optics steady but also protecting me from the clouds of mosquitoes that can be a problem here.
There are gravel roads running through the Warner Valley. But Hart Bar is easily accessed from paved Hogback Road, and provides a nice variety of wetland species. It is definitely worth a stop on your way to Hart Mountain National Antelope Refuge.