A well known Chieftain operator in Hotham used to fly via their own GPS waypoints to get in when others could not. Until one day it didn't work for whatever reason and they are no longer with us, as well as two fare paying passengers. The procedures have fat for when things go wrong, lose an engine or simply lose navigation or have an electrical failure while bungling around in IMC in valleys and you become the next statistic for the charts. Might even be as simple as a downdraft or ice in the wrong place and you can't climb as much as you would like to and its all over.
There's a well known SAAB 340 accident where they lost control while flying the valleys out of Innsbruck. They managed to stuff up the GPS tracking, and while fiddling in a panic to re-enter because of the terrain all around, they accidentally disconnected the AP and flew into the ground. If two airline crew can stuff it up, whats a single pilot PPL, IFR going to do when the nav screens don't make sense in IMC with hills around and 5000ft below LSALT.
Everything you described after that is UNSAFE and ILLEGAL.
Spot On...