If you're referring to from the kill site to the take-out, i usually drop my meat (don't be a weirdo) inside the pack and stack my cape inside a game bag or trash bag with head attached. I rarely allow myself time for skinning the skull off the cape at the kill site. So, depending on how bloody it is, it goes on top and secured inside my backpack body with top lid secured over it (horns where ever and however they fit best for transport).
To do a good job on your pre-taxi work, it takes a few hours, which usually isn't prudent to spend at the kill site, so the head stays attached until back at base camp.
But if it's early and you have good weather, you get get your pack slimmer and more efficient for pack out if you remove the skull and separate the cape. in that case, the cape gets dropped into a 14X20" TAG Bag and the skull secured however it fits my config. If you know what you're doing with hands on skills, it'll take you about 20 minutes extra time to separate the skull from the cape at the site.
LB
larry