Yes the trusted paths … un documented !
For me 40 years programming around 7 directories, plus a couple of temporary \compiled-client.
Re load them all by Vovka you can use Autoload function to load once command is typed, I use also (if (not xxx)(Load "correct lisp")) the xxx is defun name.
One directory has 116 lisps as a commercial product easier to maintain, written 30 years ago and keeps getting added to, need to join some to shrink that number but when you look at 30 year old code realise how wrong you did it then.