Dipper and Mabel are going to be so fucking feral when they get back to their home. At first the thought was kind of funny - Mabel always tossing her grappling hook around or lugging around Waddles, and Dipper literally scrawling hundreds of symbols and runes onto his wall, just in case - but then it got sad really quick. Dipper being unable to go to sleep most nights, scared that Bill was going to find him at his most vulnerable. His parents having to adapt to the deep bags always lurking under his eyes and the way he would jump at any sudden movement. And his parents wouldn't get anything out of him most of the time, the boy so afraid that his parents might get caught up in the huge mess that was his and Mabel's summer; now their life. And sweet, kind, pacifist Mabel; who can now fight dirtier than the scum of the street. Although she hasn't outgrown her childish behaviour, she often lapses into solemn expressions and watches everyone closely; like something could happen at any moment. Like someone could hurt themselves or simply disappear. Their parents are confused and concerned when Mabel moves into Dipper's room - they had stopped sharing a room a few years ago - but Dipper can't sleep without knowing if Mabel's okay, or a comforting presence to wake up from his night terror's to, and Mabel can't wake up every morning to a zombie, rather than a brother. But Mr and Mrs Pines have raised those kids for twelve years, and they have always understood the two's needs, and have been more than prepared to be there for them, or to let them be. So they learn to make a bit more coffee in the morning, just in case Dipper has had a bad night. They learn to leave blankets out everywhere, in case one of the sleep-deprived twins crashes there for the night. They start to tread louder, so not to startle their kids, and they take to wearing the start bracelets, charms and symbols that their two kids all but force on them; anything for their kids to feel better, safer. And it begins to work. It takes months maybe years, but the family learns how to function. Grunkle Stan becomes a common part of their life, as well as the many other friends that the twins had made over their summer in Gravity Falls; Wendy and Soos stay for weekends whenever they can, and even Pacifica has visited once or twice, just to check up on them. So when Great-uncle Ford comes edging through the door, Mr and Mrs Pines just pulls out another chair and sets up another bed. They'll do anything to keep their babies safe, and if that means rolling with a few punches, their more than happy to do it.
Okay, so I don't know if anyone's talked about this yet, but while watching Gravity Falls I noticed something about the title sequence. The first few times I saw the part where Dipper is pointing out that huge footprint to Grunkle Stan I merely thought that the three Pines were going on a monster hunt and were tracking some sort of monster. You know, family fun time. When it became evident that Grunkle Stan 'didn't believe' about the supernatural stuff the scene became rather sad, as I then realised Dipper was trying his best to prove the supernaturals' existence to Grunkle Stan. The poor little noodle would probably take Grunkle Stan out on one of his and Mabel's explorations in the woods to prove that he wasn't merely a child making it all up. Then it was revealed that Grunkle Stan had known about the supernatural all along, and it all became clear to me. Grunkle Stan was merely pretending that he didn't know what Dipper and Mabel were talking about (you know, in order to protect them), but while he stood there putting on an air of scepticism for the kids, he was actually wondering what type of creature had made the footprint, and whether or not he needed to get his two kids out of there before it all went pear-shaped.
From the very beginning Alex has been hinting at Grunkle Stan's true persona, and it's simply amazing to see it all unfold and reveal it's true form.