Here's the story.
My parents are 54. (Well, my mom is. My dad will be in September but early on began saying he was whatever age my mom was after her birthday in March because she didn't like to feel "older" :o)
They got married at 18 and have two DC, my twat of an older brother, and me.
We live in Minnesota in the US. My paternal grandmother is originally from here, but moved to a different state when she was 20, met my grandfather, had my dad and his siblings. She brought my dad and his siblings to Minnesota on holidays when they were children and my dad always loved it, the forests and lakes etc.
He grew up and married my mother, who had always lived in this other state, as did all her family. We lived there until I was 8, when my Dad convinced my mother to move us all to Minnesota as he had always wanted. (Not just Minnesota, but a very specific small town in Minnesota that he loved.)
My mother...hated it. She is much more social than Dad and missed her family, who now lived a thousand miles away. She told him she would give it a decade as my brother and I would both be out of school by then. That was 24 years ago.
They bought a century old log house on 11 acres next to a river and worked on making it their dream home. I am biased of course as I grew up there, but it is gorgeous now. :) They did all the work themselves and turned it from a place with no running water or electricity into a house that an editor offered to feature in a magazine.
My dad loves it. It is all he's ever wanted and he feels settled there. He is very happy with his wood stove and his books in the winter, and his fishing boat in the summer. He doesn't like people (well, individually he does, but not crowds) or traffic. He has good friends in the small town as well.
My mother doesn't love it (especially the six months of snow) but she does like the house and land, and has some good friends too.
The only fly in the ointment is...me. I now live five hour's drive away with DH and our two DC.
My brother isn't likely to have children (at least not on purpose) so wherever I live is where my parents' only GC will be.
My mother hates living so far away. She and my dad do see the DC every month or so. They come to us more often than we go to them (DH can't often get away and I don't drive) and DD is 14 months and still has a hard time on long car journeys. I think she's been to theirs about 4 times...maybe three?
Anyway, this contact is enough for my father and for me too, but it is not for my mother. She wants to be able to be really involved with my DC, to be able to attend more school things, have them over on a whim, etc. That is the way things are with my PIL, who live about 15 minutes away.
Added to which, my mom would just like to leave the small town and have more to do in general. She's, again, much more social than my father in terms of wanting to go to different restaurants and shops and the cinema and all of that, none of which are really available close to them.
Both of them can work anywhere. My mom runs an Etsy shop where she sells vintage stuff and architectural salvages and things like that. My dad...well, it's hard to explain what he does but he has his own workshop and could work out of any large shed or garage.
I have told them I'm going to learn to drive and will bring the DC to see them more, but it's hard as DS is in school. I did take them for a week this summer and then another long weekend, but with DS's activities it's hard. When we go we stay in a cabin belonging to my dad's side of the family. If they moved, the cabin would still be an option for my dad...he could go stay there and fish with his friends, etc.
So. My mom wants to move closer to me and the DC, and just to be closer to a city and more things to do while she's young enough to enjoy them. My dad wants to stay right where he is, in the home he's worked so hard on, in the town he's always wanted to live in.
It's so hard because there's really no compromise. One will get his/her way and the other won't.
Sorry for the novel! Also in sort of feel that neither of them is BU as such, but it's on my mind and I'm bored so...in your view, who is BU? :)