I had a retired 747 captain who wanted to upgrade his PPLH (with 700 hrs helo) to a CPLH. All went reasonably well until we got to the nav phase.
He could not hand-fly the chopper, visually navigate, and talk to ATC at the same time, or even within the same minute. When he saw the problems, he sold his helicopter and went back to big jets on a contract basis - and subsequently did the first-ever inadvertent 747 nose-wheel-up landing in Sydney.