Change the world the client connects to

Head to start and search: 
%USERPROFILE%\jagexcache\jagexlauncher\oldschool

2

Open the file called "oldschool.prm" in Notepad

3

Look for the line that says:

Dcom.jagex.config=http://oldschool.runescape.com/k=3/l=$(Language:0)/jav_config.ws

4

Change the line to:

Replace ## with the world number you'd like to connect to. (e.g. oldschool6)

 5

Save and close notepad editor.