Will SQL Server be able to serve workstations over a WAN?
I'm talking about the kind of WANs that a very large organisation (such as a large company or government department) would utilise to create a network between different buildings in the same town.
Yes. It will run over any TCP/IP network. Even the internet. I've seen it operate over 1.5Mb links and for doing basic stuff it's just fine (maintenance, etc).
It may however be unreliable or slow, but that entirely depends on the network itself and is not a byproduct of SQL Server.
I wouldn't want to run a heavy application over it though.