Yes, you can download your work area or work package at any point. You do not need to be in the area to download your work.
For example, if you are going to be working in a rural area where you know the mobile signal is going to be a problem, you can Download a work area, or a work package while in an area with a good signal, or even at the depot before you travel to your assigned work area.
You will still need to be in the assigned area to record your work, but an internet connection is not required to perform inspections; Only to log in, download a work area or package, or to upload your work.