Series 2 TiVo with TW Digital Cable Conversion

I know there were some threads posted years ago about cable companies changing to digital signals, but most still offered analog as well for basic. Time Warner has gone ALL digital. My Series 4 TiVo now has a cable card and a digital tuner attached. For a SHORT time, my old Series 2 was still getting channels 2 - 13 basic broadcast networks, but now those are also no longer available. I have lifetime service on this machine and really want to continue to use it. I can not afford to get a completely separate cable box @ $15.00 a month, BUT they are offering free tuning adapters, that are sort of like a cable box, but with limited channels and no OnDemand services. My question is, would that work? And how does it work? If using it with a TV or VCR, they would be set to record channel 3 and then the box would be set to the channel. TiVo doesn't record that way. I am not that tech savvy, so I could use some step by step instruction if someone knows how to make this work.