As others have already pointed out, the way the new Matrix works makes things a lot more flexible for you as the GM. You can still go with a diagram of systems, because it's good to at least have a frame of reference to go on so that you, at least, know what your players have to get to and why. And I think it's particularly a good approach just so you can manage the host and its defenses, not to mention to determine who else might be using the systems in case the players indicate their presence and they have to react.
One word of advice. I made the mistake of making a host too complicated, mainly out of a drive to make the host a bit challenging. Most of the time, unless you're talking about a major secure facility or something, most places, like your hotel, shouldn't have the best of security, unless your hotel caters to exclusive clientele, and even then what do they have to do? Mainly, keep their records of who's there safe and secure, and control access to rooms and the whole hotel. That narrows down your host structure considerably and actually can make it easier to defend, since you know where to put your best available defenses.
You really want to throw your players for a loop? Just have your hotel with rooms that require a physical, metal key to get into and out of. Sure, the PCs could pick the locks, but at least they won't do that through the host, right? You'd be surprised how often this messes up PCs plans. However, doing something like this should be done sparingly. If your players are used to getting their way through the Matrix, you might throw this at them to keep them on their toes, but don't do it too often.
