Update...
I pulled everything apart, and checked the voltage output from the RR....it's putting out ~15.8v. I also ran an ohm check on the stator connector per the manual, and it's 0.1-0.2, which seems to be in the right range but my multimeter doesn't read as accurate as the specs call for. Considering that the RR is putting out +15v though, the stator should be fine? Also, I checked the ground connection to the engine case, and it's tight.
However, with the battery fully charged (~12.8v) and back in the system, I'm still only getting ~12.2v at the battery at RPM. I've even tried another battery, but same results. I even removed my aux lights from the equation thinking they might causing an issue somehow. No change. Why the drop? What am I missing? Thanks for everyone's suggestions!