Back in the day, my biggest inconvenience was getting off the couch to change channels. I love how life has gotten so much "simpler" with all this technology.

I am muddling through as best I can and, as I understand it, if I put a bi-directional splitter on the incoming line with one coax feed to the Magnavox, and the other to the cable box, I will be able to see/record any channel the cable box receives (recording one, while watching another). Without a splitter, and assuming all channels are scrambled by Charter (pretty sure they are), the incoming line would have to go to the cable box first and I would only be able to record whatever channel the cable box is tuned to (whether or not I'm watching it at the time). Without the cable box (and using only an antenna), I would only be able to see/record OTA channels (recording one while watching another).
The Magnavox has been ordered and I am looking forward to receiving it on 4/1. I fully expect to lose an entire day of my life trying to get all this hooked up and running properly (lol) but I will get back here with my results. Mayhaps my trials and tribulations will help someone else.
In the meantime, if anyone meandering through these posts is more tech savvy than I and can offer some insight, I would welcome it.