The only way to do a nandroid will be with a custom recovery, so you are correct. The root will not stick through the GE RUU flash, so after you flash the GE RUU, you will have a device that looks like it just came from the google play store, except that you will have an unlocked bootloader, and s-off. This means that you will have the stock recovery and will not have root. If you want to go back to stock you need to flash the 1.44 hboot and relock your bootloader before you flash the RUU for your carrier. Also of note, if you are going to unlock your phone's sim, make sure you do that before flashing the GE RUU, I went back to stock for the sole purpose of unlocking my sim.