They're simple. The passenger is the easiest. You don't even have to jack up the front of the truck. Just remove the airbox, and you can pull the shock tower right out. The driver's side requires a little manuevering to get through the brake lines, but it's still pretty easy.
Plus, the Rancho's are even easier than normal gas-filled shocks since they don't fully extend if you don't have them tied up. You just drop them in and bolt them up.
JM