>The modem is a piece of shit and can only have one cable coming out of it
That is literally how all modems work.
Having two routers acting as routers is bad. Double NATing means more latency, harder time connecting in games, VOIP etc. Stick your best router at the modem, use as many switches as you need from there. If you need more wifi points thats a different thing.
I can draw you a diagram of the fucking ghetto setup if you want? Basically this connection is being shared between several different buildings and needs at least 3 routers.
I'll believe that it needs 3 Access Points, not 3 routers.
Bridge mode.
Explain further please
Put the other routers into AP/bridge mode, so that the modem-connected router handles all the routing. Devices will see each other across buildings, but that's what VPNs are for.
This small company wants to get rid of their prehistoric server (Windows Server 2003), but want to keep sharing files between their office computers (4-6 PC's) as well as having access from outside (e.g. smartphones) but this is not essential.
What would you suggest? Cloud services? It is a company so they need some security as well, therefore services like Dropbox are discarded.
They want it cheap, free if possible.
Oh, I forgot the pic. I know you want it.
office365 with sharepoint.
