Plan for running Windows on new MBP

I need to have access to Windows occasionally for work - I have an OLD laptop I've been using for this, but recently bought a 2012 non-retina MBP. I replaced the HD with a Samsung 256 SSD, so want to keep SSD space as open as possible since I only need Windows a few times / month. I run Parallels on my destop (Mac Pro) at home, but don't want to use up the space for it on the new MBP, so here is my plan. Should it work?

Buy a 64gb USB 3.0 memory stick (a FAST one, $80 or so.) Buy Windows 7 Home edition ($100?). Install Win7 on the memory stick - the Win software I require for infrequent work use is very 'light' (Java and most extentions, and a couple custom Win executables), the OS and program stuff should easily fit on a 64gb stick.

If I need to boot to Win7, just boot with the memory stick installed - shouldn't even have to use BootCamp, right?

This seems too easy for my requirements, what am I missing? What are the potential 'gotchas'?

Thanks for your help,

John F

LV NV