Nothing is so bad that it can't be made worse. I just went through this process without benefit of the advice in this conversation.

Instead, in my thrashing, trying things that might work, I set the default kernel to one of the RPi kernels. This turned out to be a terrible idea, because this disabled Mathematica. The RPi login dialog would come up whenever I tried to start it (I had never been able to figure out what the Remote Development Kit dialog was looking for) so the system was locked into a loop. The program managing the remote login dialog box couldn't be stopped by the Mac's Force Quit, the OK button, the cancel button, or the window close button. Mathematica itself could be stopped in the Mac Force Quit window. The problem infected all versions of Mathematica I had on my Mac, and it persisted through Trashing them all and reinstalling 9.0.1.

While I was casting around Google, looking for a way to avoid reformatting my hard drive, I had Mathematica idling in the background, blinking on and off in the Force Quit window with a "(not responding)" label attached. For reasons unknown, after a long time Mathematica's palettes finally appeared (pink) but the main menu was active. I was able to follow the instructions above, clean out the kernel list and reset the default kernel. A Christmas Miracle? Probably not, but pretty mysterious nonetheless.

So everything seems to be running fine. I'd still like to get the remote kernel running on the RPi, but I'm not eager to start messing with the RDK again.

Has anyone had success setting up the remote kernel from the Evaluation menu?

So far I've tried
What next? I've been able to establish the link and run wolfram from the Mac Terminal via ssh, but not from a notebook. 

Any suggestions  would be welcome.

TIA,
Fred Klingener 

I wanted to follow up with some more information on the RDK connection issue. I moved my Mathematica Home Edition to a different PC on my LAN. After installing the RDK, I was able to successfully connect to my RPi. It's a mystery to me exactly why that is the case. The 2 PC's were very similar wrt hardware and installed software. The only thing that I can think that might affect the ability to connect is that on the original PC, I had installed Oracle's Virtual Box for running to virtual machines. Nothing like that is installed on the 2nd PC that connected to my RPi. I believe Virtual Box might do something with virtualized NIC's that may make that PC look like it has a different LAN IP address? I'm only guessing, though. I was able to connect to the RPI MathKernel through an ssh terminal on the original PC.