Remember Sid and Marty Krofft's 1974 TV program Land of the Lost, which featured a family that was trapped in an alternate dimension with dinosaurs and other beings?
How about a LOTL-type scenario for MLP:FIM?
A human family, living on Earth (NOT the world of Equestria Girls), headed by a single mother named Jane Conroy, who recently divorced her husband and won custody of her son Wayne, her older daughter Jen, and her younger daughter Cyndi. Miss Conroy also recently lost her office job with a leading bank in Chicago.
Mrs. Conroy and her three kids are traveling by car to California where she has obtained an interview for a new job. On the highway in Kansas, the auto breaks down just as they are trying desperately to flee an oncoming tornado.
The Conroys' car is swept up into the twister, and they somehow land in Equestria, in the Everfree Forest. Their car is a wreck and cannot be repaired. The Conroys also shockingly discover that they have magically transmogrified into ponies.
Mrs Conroy has become an Earth pony, Wayne has become a Pegasus Pony, Jen a Unicorn pony, and Cyndi an Alicorn.
Curiously, the Conroys have their actual names as cutie marks.
Mrs. Conroy leads her family through the Everfree Forest and discovers Ponyville.
Pretty soon, the Conroys come to the attention of the Mane Six led by Princess Twilight Sparkle.
After a day or two of adjusting to their new lives as Equestrian ponies, the Conroys learn from other ponies on how to make a living in Equestria. Jane Conroy discovers she's still talented in preparing food, so she lands a job at the Sugarcube Corner helping Mr. and Mrs. Cake and Pinkie Pie in making and selling cakes and other food.
Occasionally, Mrs. Conroy helps out Princess Celestia, Princess Luna, Princess Cadance, and Twilight as a personal secretary. Mrs. Conroy even occasionally drinks tea with the Alicorn princesses.
Wayne Conroy starts training under Rainbow Dash to use his Pegasus talents to help control Ponyville's local weather, and his sister Jen starts training under Rarity to become a fashion designer, helping Rarity at the Carousel Boutique.
Young Cyndi Conroy, possessing rare Alicorn magic, is still young, and is watched very closely by Twilight Sparkle and her own mother, occasionally goes on an emotional rampage, crying that she wants to go home (Earth) and uncontrollably uses spells that can cause considerable damage. Cyndi is enrolled in the Ponyville Schoolhouse, being taught by Miss Cheerilee. Cyndi has developed a close friendship with Fluttershy, who is teaching Cyndi about handling animals. Cyndi is also close friends with Pinkie Pie and the Cutie Mark Crusaders.
At one point, the Conroy family enlist Discord's help in trying to return to Earth by combining Discord's magic with Cyndi's Alicorn powers. They fail.
Another time, Cyndi and Discord try to combine their magic in order to return the Conroy family to human form. However, after about two minutes in human form, the Conroys return to pony form.
At one point, Wayne Conroy gets into a physical fight with Applejack after claiming that the apples grown at Sweet Apple Acres tasted worse than pony excrement, but they pretty soon healed their relationship.