So after following a few pointers, I came across the Michael Blank’s SimpleDCC site. The cool thing about this is that he is using an Arduino as a DCC control unit without something like the SPROG as in interface. He is have the Arduino itself send out the DCC signal alone with a booster to power the trains. I need to study both his interface and the programming some more, a lot more, but it really does hold out the hope that I can either use just the Raspberry Pi with an Arduino, or even just the Pi all by itself, to be a complete JMRI/DCC controller.
Guess what I really need to do too is dig some more into the JRMI code and the Linux installation. I don’t know whether it would be easer and faster to use the Arduino hooked up to the Raspberry Pi to do the translation to DCC, or whether I should have the Pi do that also. Another consideration that starts to come in is the speed of that entire process. But then again, that is what experimenting is there to find out.