Are there any special adjustments that need to be made (on the SQL server side, or the database/query side) to accomodate for communications over a slow(er) WAN link? We have had slow performance ...

With JSON now the default format for moving data between clients and servers, SQL Server adds JSON support to make it easier to get your data out of the database and down to the client.

I need to connect to an MS SQL Server and use SQL Query. How can I get my hands on a free client if something like that exists?

Client-server applications emerged with a graphical user interface coupled to a back-end SQL database (frequently Oracle Database or SQL Server).

Install the Microsoft SQL Server Client for Windows 95 or NT and Microsoft SQL Server ODBC Driver (32 bit). Refer to your MS SQL Server documentation for more information.