Hi. I'm also an old mr user, and one of the things I found most difficult (but also most pleasant) when changing to Corona, was not to do things the "complicated" way I was used to! Corona is actually straight forward :)
As Lucutus said, leave the render settings at default (exept the choice of secondary solver) and work with materials and light instead.
The only thing I really miss, is the way mr worked with the standard Ink&Paint material. Hopefully there will be some sort of ink/toon shader in Corona at some time (not too far away).
Regards