The Pines Cabin was in a very specific spot. Dipper had decided as much when he, Manly Dan and Wendy had begun planning to build it. First it was deep in the woods, with a collection of paths leading to the Mystery Shack, the town and a nearby road. Second it was built next to a stream which ran through the back garden and finally it was equidistant between the Mystery Shack and the glade that housed Bill Cipher's statue. Dipper had done so to be the first line of defence if the demon ever returned.
To say he was paranoid about this occurrence was an understatement. He checked the glade at least once a week, as well as surrounding it with an electric fence. Nobody was going to see the demon without his express permission, he had to be sure.
This had only gotten worse when Summer was born. She'd been alive for less than 3 months and Dipper had barely let her out of his sight. Wendy hadn't had to get up to see her at night once, her husband had already been there. Wendy had noted the behaviour as odd but it wasn't till the other strange occurrences started happening that it was all put together. First Dipper had disappeared for most of a day and returned with a fistful of unicorn hair. He had proceeded to ward both the house, the Mystery Shack (again) and the path between. Then he had brought together the major factions of mystical creatures in Gravity Falls and made it very clear what would happen if they ever touched his child.
But it had all come to a head when she'd woken in the middle of the night, no crying baby just restless, to find him staring at the baby monitor like it might explode. And just like that it all came together, he was more than just scared of her coming to harm, he was terrified. She had reached out towards him, gently stroked his face and pulled him into a kiss. She then began playing with his hair, a surefire way to calm him down, and he had slowly fallen asleep. This was her strategy every night, clinging to him tight so he wouldn't move unless he had to. Wendy understood that he needed to stay by his oath, both to her and to the town of Gravity Falls. The latter being to protect and serve. But she new that right now the only thing needing protection was her husband and she was more than willing to oblige.