Did it in 2000. It's pretty flat--our Cateye altimeter showed 960ft at the end of the day. One rest stop at 34 miles, another at about mile 70, which may be important information if either of you is reticent about peeing by the side of the road with bare rice paddies offering 10 miles of visibility. The route sheet cautions you about railroad tracks at about mile 28 (or at least this was the case in 2000) and this should be taken seriously. I thought I had a good 90-degree line over them and I still caught and torqued our rear rim enough to have to replace it later (but it stood up to the following 70 miles, happily for us). It was a gray and windy day the time we did it, with the last six miles in torrential downpour. We met and chatted with a number of nice teams as we went along the route. Traffic was light for the most part. My wife and I did nine centuries that year, and this was our least favorite, mostly because of the flatness and the spartan support (we really like your Wine Country Century--great scenery AND roasted potatoes--it's high on our list!).
Don't know about accomodations in Gridley. We stayed down in Yuba City and drove the 20-odd miles to the start.