Oatmeal with maple syrup and keyboards don't mix.
The degree of difficulty here is the sheer number of steps involved. None of them by themselves are difficult. And paying extra for the whole upper case rather than replacing just the keyboard was key (heh heh) for me.
Patience. The magnetic pad for holding parts is crucial for me. And a towel. I put a terry cloth towel on the table. It keeps any dropped tiny screws from bouncing off into the ether.