If you want to do Blue Bayou, I would book it in advance. They do take walk ups but the shortest wait I have ever heard of was about 1 hour (and that was in the slow season). I would recommend going to the Disneyland website and seeing which restaurants they suggest reservations for and then make them for the ones you want to try. As you probably know, dining as DL is way different than dining at WDW. Most places are walk up and first come first serve. However, they do take a lot more reservations then they did in the past.