I was hopeful when I last posted. Sadly to say, the config option for connecting to the host serial port is grayed out, preventing me from accessing the serial port. The Internet appears to be in disagreement as to which version of ESX or ESXi actually supports the feature.
Then again, it could be my machine. My serial port is actually located on a PCI card and not the motherboard. More than likely, I'll need to resort to adding drivers to ESXi again (not something that I'm looking forward to).
I'll keep poking at it and let y'all know if I get it running. I may have to resort to a eth-to-serial adapter.