Made some good progress since last check in on the hardware prototype devices.
I received my ATAES132s, and I finished wiring the SubModule board! I threw some OLED test code on the Zero and ran I2C Scanner to verify everything is happy on I2C. Still have to verify that the HopeRF modules work on both the HAT prototype and the SubModule prototype, but I'm 95% of the way ready to start writing some software/firmware.
I plan on busting out my RTL-SDR module for some basic RF analysis, so I can get some insight into how well the prototypes are performing. I also put in an order for some Microchip RN2903 LoRa modules to start prototyping using those radios in place of the HopeRF RFM69-HW. I'm going to be running that effort in parallel, as it seems like the LoRa modules will have better overall range than the RFM69-HW modules, but I won't have my hands on any for another couple of weeks. Also, due to their size, I will have to re-evaluate some of my mechanical decisions, but for the most part not much should change.