I've put together the schematic and breadboard layout in Fritzing (I'll be uploading the files soon) and put together the first part of the circuit on my breadboard - the PIC, display, rotary encoder, ICSP header, and Mode button. Now, to program the PIC so I can test this stuff out...

And now I'm starting to realize why AVR/Arduino has been replacing PIC as the darling of hobbyists in recent years. PIC's architecture is... peculiar. The few open source tools that support PIC programming aren't updated like they used to be. (PikLab no longer builds on my system, for instance, and SDCC's PIC support is still experimental) There's very little library code available from the community. (it looks like I'm going to have to code my own PID controller) AVR, on the other hand, is quite well supported by open source tools, and has an active community contributing reusable code for it.

In short... if I actually had some AVRs on hand, I'd probably use them instead of the PIC. But since I don't... on with the coding.