For anyone who might be interested in connecting directly to RS-485 devices with a completely hardware solution, I have managed to make this work in a very clean, simple way. As discussed in other threads, the RTS pin is not easily utilized for flow control on the Connect ME. Others have tried, apparently with mixed results, to do a software work-around. This required no software changes. The same software that works on the development board works with this board.
If anyone is interested, reply to this topic, and I'll post a description of my solution.