A happy ending means different things to different people. It never means the story's truly over or that nobody had any more trouble at all. And it definitely didn't mean an absolutely perfect life for the Winchesters.
John and Mary's marriage still had rough spots, and Mary ended up splitting her time between Lawrence and Bozeman. Adam kept up the sulky teen routine until he left for college, although he never got to the point of disowning Sam and Dean to their faces, and once he moved into the dorm, he threw out all his protective training in favor of being "normal." Only his brothers' quick response to one of the visions Sam had started having shortly after moving to Bozeman saved Adam from falling victim to a couple of ghouls seeking revenge on Mary.
Sam and Dean hit their own share of speed bumps in learning to live on their own. The demon who turned up claiming to be Azazel's daughter was only part of it. They got along with most people in Bozeman okay, but there were laundry questions and cooking mishaps and books that got coffee spilled on them and mechanical problems and political questions that confused the hell out of both of them. But within a year, they were pretty well able to fend for themselves, even when Mary was there to help with housework. Hunters started to seek them out for advice, and the neighbors did accept them for who they were. A few of the oldest Irish old timers even called them fairy doctors.
And then they hauled off and got married.
It was both sudden and unsurprising. Jo Harvelle wanted to become a hunter, despite Ellen's objections, and although she spent her weekdays at college, her weekends were largely devoted to learning the business. Ash's description of Sam and Dean intrigued her, and she ended up drifting to Bozeman once or twice a month, often dragging along a friend whom she was trying to interest in hunting. She wasn't sure which brother she liked better, though over time she leaned toward Dean, but most of her girlfriends were either put off by the boys' fairy-touched ways or hit on one of the brothers—especially Dean—way too strongly. Dean almost fell for one friend, Cassie, until he made some distinctly childish (but not bad) remark that caused Cassie to flounce out of the house and drag Jo with her. Dean cried for a week.
But then Jo met Jess Moore, who wasn't all that interested in hunting per se but somehow got Sam in a way Jo's other friends hadn't. She wasn't even put off by the twenty years in Faerië. She truly loved Sam for who he was... and Sam liked her a lot. And Dean started to realize that Jo felt the same way about him.
Finally, a year or so after Jo first introduced the boys to Jess, the girls came up for a weekend, and Sam and Dean met them on the front steps. Sam took Jess by both hands and looked at her for a moment, and whatever speech he'd meant to make, what came out was, "We should get married."
Dean shyly took Jo by the hand, studied her face the same way, and whispered, "Yes."
Jo suggested Vegas, but Jess said her parents would kill her. So after a few quick phone calls, the Winchesters' extended hunting family and the Moores had a week to get to Bozeman for a very informal wedding officiated by Pastor Jim. The Moores weren't thrilled to see so many "rednecks" among the other guests, but Sam and Dean charmed Mrs. Moore enough that she and Mr. Moore did eventually give their blessing to the union.
The couples did move into separate bedrooms, but nobody dared ask how the boys' mental link affected things, and neither they nor the girls ever told. They were all quite happy, though, and before long, Sam and Jess had twins and Dean and Jo had one on the way.
One summer evening in 2010, the couples took the children outside to play in the backyard as they often did, seemingly unaware that they were being observed by two figures lingering in the shadow of the forest that bordered the property. Said figures, male and female, only watched, though after a while the ball that the children were playing with began rolling off and bouncing around as if it had a mind of its own. The children shrieked and giggled as they ran after it, and the male figure chuckled contentedly as he led them a merry chase.
"This isn't how the story was supposed to end, was it?" the female figure asked.
"Nope," replied her companion, popping the p. "The world was supposed to end last month—literally or just from Dean's point of view, depends on who you ask. I dunno about you, but I kind of like living."
"So you summoned a leprechaun?"
"Hey, the boys' childhood was going to be stolen from them regardless. I just figured... better to let them have something in exchange."
Sam looked into the trees then and caught sight of the pair. A moment later, so did Dean. They made eye contact for a long moment... then smiled slightly, nodded, and went back to watching the children.
Kali snorted. "You're pathetic," she said affectionately.
Gabriel shrugged and popped a candy in his mouth. "So I like happy endings. Sue me."
A/N: This story was inspired, at several removes and in reverse, by George MacDonald's The Golden Key; really, about the only points carried over are the rough 1 hour = 1 year ratio and the character of Grandmother, who is still only loosely based on MacDonald's fairy. There are probably also some influences from ficwriter1966's "Legend" (on LJ), though I've tried not to swipe any plot points directly. The title is Scots Gaelic for "little heroes."
I think I've seen summaries for other stories where one of the boys was taken by the fairies as a child, but I don't remember reading any of them. So any similarities are a case of great minds thinking alike.