UPDATE - Reinstalled RCM today - forgot that I had the brake switch unhooked and removed.

With the repaired RCM in place, car started right up. No dash lights on. But I'm stuck in park. Didn't think to look at gearshift indicator, I bet it's going to be a black rectangle instead of a P. Reinstalled brake switch, plugged wires back in. Still stuck in park.

Feels like progress, but not all the way back yet.