No, it's not a direct parallel to Astral Space.
Where Astral Space locations are necessarily ties to Physical world locations, this is not the case for the Matrix. There is no correlation between grids and hosts and physical locations. AR is like astral perception in that you see the matrix world and the physical world at the same time. VR is like astral projection only in that you cease perceiving the physical world.
So in the example you give:
Joe SINner sits in a cafe and browses the stock market reports and whatnot. He's either looking down at his commlink or a sheet of electronic paper in a manner similar to using a smartphone or tablet in the real world (neither AR nor VR) or, more likely, he's likely paging through holographic popups that he can see via his image link. His persona is technically tied to the physical location of the device he's using to connect to the Matrix (his commlink). So if anyone wants to start hacking him, if they're far away they have to suffer distance-based noise. But just as you're able to call him at his commcode from anywhere in the world (that has matrix signals...), you're also potentially able to hack him from anywhere. Assuming you can negate or deal with the Noise penalties.
So if Joe wants to dip into VR for some entertainment or perhaps a business meeting, all that really changes is he loses the input from his physical senses. Now ALL he can see are AROs and icons and so on. If he wants to access various matrix services/hosts around the world, his commlink doesn't change its physical location and so even though he "leaves" in a virtual sense, anyone nearby his comatose body can still see his signal bright and strong just as if he were still in AR.
So, a couple of tenets:
You can always perceive things that are physically nearby (unless they're running silent). This "nearby" distance was defined as 100m in 5e, it's deliberately undefined in 6we. Could be greater in areas where the matrix is less busy, and less in areas where the matrix is more busy. A good rule of thumb is if the item is close enough to be seen clearly in a physical sense, you should also be able to see its icon as well when in AR/VR (barring running silent).
Hosts are ginormous icons that loom over the matrix "below" like gods. You can see them from anywhere, unless of course they're running silent and trying to be discreet.
There's a bit of a conundrum in what you can see inside a host from outside the host. I call this the Host event horizon. It's something that's being hashed out behind the scenes, but to give the 5e version: anything inside a host can't be seen from the outside the host, and vice versa. It probably will be less rigid/harsh for 6we.
AR personas: can "leave" their physical location to interact with devices/hosts around the world. But remember distance based noise. Now when this happens... say: Joe SINner wants to virtually visit Dante's Inferno in Seattle, his persona remains in place wherever he physically is (but see also the host event horizon paradox). But when he's inside the club's host, his digital avatar is able to interact with other avatars also in that host. Despite wherever THEIR physical locations might be. Normally, these personas inside the host can't see or be seen by the club patrons unless they too bother to log into the host. But see the example in 5e: hosts CAN, if they explicitly desire this, render the visiting personas as holograms for patrons not even inside the host to see. In this way you can digitally interact with the club goers. It's more realistic if you're in VR. But again, the establishments have to have gone through the bother and (unspecified) expense of setting this up. Normally you CANNOT see AR/VR personas whisking around as they explore the matrix because they're not moving around the matrix in a way that corresponds to physical locations.
