Fred,
I use ViaCad --> Cambam --> Mach 3 for milling on my DIY router/mill. It definitely works. This was my first journey into CAM, and everything worked very well together.
I've used AutoCAD in the past. I now prefer ViaCAD now. Cambam is good, easy to learn, and very logical. However, it doesn't have a visual simulator, so it uses CutViewer, which is an additional cost item. I'm not too fond of CutViewer, but it usually gets the job done.
--Robert