Well, the other day I was watching youtubeer (you tube with a beer in hand) and came across a video of a guy building cnc kitchen cabinets using a software pack called Cabinetpartspro. It looks awesome for cabinets as it cuts out the need for any design/cad requirements. Anyway. I was chatting with the developer and wondered if he had a marlin style post processor. He hasn’t made one yet, but suggested they are easy enough. I suppose this is more for the real gurus (Jeffeb3) but what would be specific for cutting cabinets that would need to be added via post processor to make it seamless with our wee little marlin boards. It currently makes a .cnc file which is just gcode, but what kind of header would need to be configured, I guess that is my real question.
The header is very machine dependent. Ideally, it would be user configurable.
Big things that are needed for Marlin are because G0 isn’t treated as a full speed travel move. The easy fix is to make sure the user defines a travel speed for xy and for z. Then make sure that speed is applied to every move.
The second big issue is that Z moves need to be slower. But that is the same fix. Make sure each line has a speed defined.
There are some special gcodes Marlin doesn’t support. Like drilling holes.
I am not the expert in post processors though. I haven’t made on. I just Monday morning quarterback them 
Question about Marlin not supporting drilling holes. If I was to use fusion 360 and in the manufacturing tab click on drill holes. Will the G code not export properly?
Fusing 360 CAM drilling works fine for the MPCNC. If you look at the g-code produced by a Fusion 360 drilling operation, it is implemented using standard movement commands (G1 - G4), not through specialized drilling g-codes. Some g-code versions support “canned” drilling routines that have multiple movements. For example, a G83 implements a “Deep Hole Peck Drilling Cycle.” This kind of drilling is not supported in Marlin.
Thank you for that explanation Robert