I am thinking it will probably be fastest to install Windows 7 from HDD (or network sometime later). I suppose I will need Windows PE, but I haven't done it b4, how do I go abt installing from this route?
winpe is a standalone install of windows on a cd - so you'd get no advantage from using it to install. Considering how fast modern day windows installs are, it won't help much.
However if you want to use an external drive to install, you can use wudt to convert an iso to an installable disk. This dosen't use winpe in any way - it just copies files and sets up the usb drive to be an install source