What I do on my laptop is, I just configure my mouse as IMPS/2 to make any external mouse work. The synaptics touchpad is auto detected, and moving the cursor works, also both buttons work. To get the scrollbar function, tapping and multi-finger detection to work I needed to install the synaptics driver from http://web.telia.com/~u89404340/touchpad/
It's a relatively simple process, instructions included. Good luck.
EDIT: You get into KDE (after installing it) by running xwmconfig (as root) and setting KDE as the default window manager. Then you type startx at a prompt and assuming it's configured properly, it will get you in KDE.