Hi,

With regard to one of your initial issues of outdoor 'drift' of about 5' that sounds suspiciously like a compass calibration issue, might be worth conducting a compass calibration away from anything metallic just to verify.
 
Thanks for the input! I have tried a few times to calibrate the compass but I'm not sure if I succeeded or not. I've had a real hard time getting past the first step. The few times I've made it to the second step, I've spun it a number of times and eventually the screen goes away. I don't know if it's just quitting after so long or if it's succeeding but there's no confirmation screen. I'll give calibrating the IMU a try too.

Thanks!