Loved the father/son dynamics

I agree. The relationship portrayed in the book was a little bit more nuanced. While Homer's dad was a tough man and was hard on Homer, he still acquiesced to not stopping Homer from his pursuit of building and launching rockets. He actually intervened in his own way to make sure that Homer got the support from the townspeople of Coalwood (basically his employees) to accomplish his rocket-launching feats, even though had to walk the line between toeing the company line and bending the rules to support his son. He actually respected Homer for his resourcefulness (raising money to buy the high-grade steel and other supplies, traveling to a considerable distance to a site that isn't on company property to launch rockets, asking to borrow some of his engineering and math books, never giving up after all of the various "incidents" that happened, etc.), and may have been a bit proud for Homer, even if he felt that rockets weren't important. While up until the point where Homer started successfully launching Rockets, his dad always figured that Homer would be nothing more than an accountant/clerk/bookkeeper for the company. But even he started to realize that Homer just might make a good engineer like himself, even if being an engineer didn't come so easily and naturally to Homer as it did to himself (although he never went to college and got a degree, he was a very smart and self-taught engineer, under the guidance of the man who founded and owned the mine before Olga bought it). This was all portrayed by Chris Cooper in the movie to a certain extant, but it was more obvious in the book.

It was very evident in the book that Elsie Hickam was the figure in Homer's life who was the main driving force behind Homer to always pursue his dreams. She knew that early on, unlike Jim's talent with football, that it was the only way that Homer can get away from Coalwood, and she didn't want him stay as much as Homer himself didn't want to stay. And she always realized that Homer and his father were more alike than each other would have liked to believe. True, she wasn't happy when he blew her fence up, as well as having some of her kitchenware surreptitiously appropriated for making "rocket candy", and she expected him to not it interfere with his schoolwork and chores, but she had no objection to his pursuits. She was always chiding him by saying "as long as you don't blow yourself up," but that was her way of reminding him that she didn't want him suffering the fate of most of the boys who never got out of Coalwood.