Sheesh
Go to NIST.
Get one of the IGES "viewers". IIRC Source is
freely available for some.
Start out using IGES as your part file database.

This would at least assure that your parts are 100% IGES
compatable G. And open with other systems that support IGES
(mostly).
Half the work done in defining entity data & records too.

Then you could get APT source to do the CAM bits,
as a starting point .... G.

BIG Clue #1: If it's NOT 5 axes to begin with you are
already up the creek. Making 2 or 3 axes stuff is *EASY*
but making that 5 axes later is not. Making 5 axes do only
2 or 3 is simple (they are a subset).
--
Cliff