I've been lucky and have worked at home since I brought Toffee home. When I travel for work (which is non-stop some of the time), she stays with my retired parents who are home almost always with her.
Still, even working from home, I left to run errands and attend meetings. When she was really young, she stayed in a crate when I left. She has always been very well behaved though, and so I stopped crating her when she was about 4 months old. She had access to the entire house at that point (and she never abused that privilege!!).
I think a crate is a good way to go for a younger dog, and once they become comfortable in the home (and it's been dog-proofed), are housebroken, and you can trust them, you can limit your pup's access to certain rooms (or the whole house depending on what you're comfortable with).