The easiest way to start KDE from the command would be to type startx. This should load KDE straight away (being Mandy, KDE is the default), but if it doesn't:
create/edit the file in your home directory called .xinitrc (the dot is important), and put in a line, right at the beginning, which states exec startkde. Now, when you type startx, it should load KDE.
The things you did to ~/.kde/Autostart should have no bearing on KDE starting. If it doesn't even try to load X (graphical stuff) on boot, then you need to edit the file /etc/inittab. At the beginning there should be a line that looks like init:3:default (or something)...change the 3 to a 5...there should be plenty of comments in the file to help. If in doubt, at the command prompt (before loading KDE), move into the .kde directory (cd ~/.kde) and rename the Autostart directory to something else (mv Autostart eAutostart, for example).
As for the mouse...have you tried running mousedrake from the command line (even with X running)? I've never had mouse problems, so I'm affraid I'm only stabbing in the dark here.