VHS
If need be that company that advertises on Rush can transfer older graphic material to DVD; however, probably cannot do it with copyrighted material
MemoryBox or something like that? Yeah, but they are WAY SPENDY even with the discounts they offer (along with the torrent of email you get if you screw up and give 'em your address).
And yeah, that copyright deal is a show stopper.
That old VCR of mine does transfers VCR-to-DVD but practically spit on me when I tried that one time to make a DVD of one of my collection.
Oh, well. I've got to dig into that VCR for cleaning etc and I may just "adjust" some things while I've got the patient on the table. (Big ol' sinister grin)
BTW, no worries about the 4yo twins getting excess exposure to TV. Their Mommy despises The Box almost more than I, the girls are 'way smart/decided all by themselves that they didn't need or like it either and would rather play outside to the point that we've had to restrain 'em from running out the door into thunderstorms.
Only times they do watch things on TV, they'll sit for a few minutes and then launch into their own play world with the TV as background noise.
I had a DVD recorder and recorded probably about two hundred movies and a bunch of archaeology stuff from History / Science channels. It broke down and I paid the mfr to repair it but it didn't last more than a year. By then it refused to record copyrighted material any way so I just abandoned it as a recorder. As I say, as a DVD player it has no HDMI output. I am a retired TV technician... new age... left me far behind.
Your grandkids sound as if they are on the right track: get outdoors, interact with others, use their brains and learn to think, not sit at home and wait to be told what to think. Good job. :)