While I understand not wanting to invent working wheels, if you want to create a key/mouse stuffer then I recommend looking into Win32::GuiTest or Win32::CtrlGUI.

I have not used them, so no specific recommendations, but I have personally found that it can be a lot easier to rewrite existing batch scripts in Perl and then add error handling logic than it is to make the original robust. YMMV. (That experience was mostly with expect scripts.)