I have a couple of ideas for projects that I've kept in the back of my head for awhile. My advice is to just go and shoot. At least for now, don't worry about releases. For something like this, you likely won't ever need them so if they're what is stopping you from shooting, don't worry about them. It could limit what you do with the images later on, but I wouldn't think you'd be that likely to sell them for commercial use. Putting together a book isn't usually considered commercial use - using the image in an ad for the restaurant would be.
Most important - just shoot. Get started and see where it takes you (I should do the same - one idea has been kicking around for several years now).