We just spent one night at Fern Grove Cottages in a cute little cottage. It was old, funky, and cozy! The gas fireplace kept the place comfy. The grounds were lovely, even in early December! The best thing about the experience, however, was the marvelous breakfast. Freshly baked scones, yummy biscuits, fresh fruits, breakfast breads, and good coffee + good company made for an outstanding breakfast. And, the house-made lemon curd was amazingly tasty!
No, it's not plush or modern, but Fern Grove Cottages is a good choice when staying in Guerneville.