Firstly, you can use the function keys to switch through inventory, combat style, spells, etc... Most of you know of this already, but here is a list anyhow.
F5: Combat Style
Now, for the chat options. The first one is fairly obvious, when given options in the chat window there are numbers next to the options (denoted by the green boxes). To quickly select one, simply type one of the numbers.
Secondly, this works for destroying items or other yes/no options. You can simply type either 'Y' or 'N' to select yes or no respectfully.
Thridly, and this is my favorite. The spacebar works for continuing the chat. Better yet, you can hold down the spacebar to quickly continue through annoying NPC dialogs
I hope these help you in your Runescaping, I know they help me!
If you know of any others that I didn't list, please inform me and I shall add it to the list
Edited by McSwindler, 28 April 2012 - 11:17 PM.