So I had a proof of concept working several months ago and only recently started working on this project again (thanks THP!). I started back on the project using the same components I used previously, but I've since ordered and received a few new components. My immediate goal is to get the PoC back up and working with these new components.

Nothing that big: My son ate (or more likely misplaced) some of my 900mhz duck antennas and U.FL to RP-SMA adapters. Sparkfun regurgitated those for me quickly. Also, I'm trying to shrink the ultimate packaging in parallel with the PoC, so I'm switching out my Arduino Mega's to the Arduino Pro Mini 328's. 

The main problem I see with going from Arduino Mega to Arduino Pro Mini 328 is with the GPS interface and XBee module working in harmony. I was using the two hardware UART's on the Mega (one for GPS-to-Arduino and one for Arduino-to-XBee (or Arduino-to-PC)). One of these will now have to be a software UART -- but which? If any kind readers can advise I'd appreciate it. Just as a complete shot in the dark, I'd guess that the higher baud rate RF module should be a hardware UART while the 4800 baud GPS link should be software, but that's just a guess!

I'll be posting the components list in the designated section of the project page, so please look there for the current, high-level list of components used.