Father And Son Kidnappers In The 70s?

not sure about father and son, i think there was a so-called mountain man who did such a thing

Yes they were mountain men as I recall and the agent who finally arrested them made it to their camp on snow shoes after his Skidoo hit a stump or something. Would like to reread the story if I can find it.

I may have found it..
1985 in Monatana

Stories on kidnapping

I thought it sounded somewhat familiar. The younger man was hoping to marry her.

That's the story all right! Those two came to mind when I read about Bucky Phillips currently on the lam in up state New York. They're among a number of outlaws who kept the law at bay while holing up in the woods. There was one in my former home state of Missouri who held out for a long time in the Mark Twain National Forest. I think around 1990.