it might look/sound tedious, but just put on some music and make yourself some tea. it'll be over before you know it!
besides, you do this once and you'll forever have that sweet look : )
you won't regret it!
and surely there are a few tutorials/guides out there, or otherwise experiences of people doing HHKB case-swaps.
otherwise, i think the RF87U case-swap is almost exactly the same. i think the only difference is that you'll have to remove the caps of the HHKB as well.