Do they read cover to cover?!! In any legitimate trade house, the editor reads it in its entirely multiple times. First when they decide whether or not to acquire it; then in order to edit it; then to read the edited version.
I usually hear back from my editor (or PR person, if the book's at that stage) within a few hours of emailing, if it's a work day. Waiting a day or two wouldn't be cause for alarm. The amount of contact varies depending on where you are in the publishing process, but your editor is your main interface with your publisher, so there's a good deal of contract. During the editing phase, you'll have discussions about that. Your editor can and should keep you informed, either directly or through your agent, as the book goes through all the production milestones. In most cases, depending on your contract, you'll have a say in the cover design, so there's more back and forth. Once the book nears its pub date, there will be more to talk about: early reviews, marketing strategies, and lots else. At a certain point, your main contact will become the PR staffer assigned to your book, with the editor taking a back seat. But he/she's always there and accessible.
All this assume you don't make a complete pain of yourself, calling daily to demand this or that. Those writers soon find their calls are not so quickly returned, or they're returned by an assistant.