My mother lives 10 hours and our in-laws live 12 hours by automobile from us. We generally see them 2 or 3 times per year.
It's difficult. Especially when they're ill. My father-in-law is now in a nursing home, so we must always go there for holidays now, as he can go out in the care of the family for the day and we want to include him in. In the past, my in-laws would sometimes fly to our home for a holiday so that we didn't have to schlepp the kids so far. Also, they'd come spend time with us in the summer when the children were off from school.
My mother was seriously ill and nearly died a few years back and while I was with her for a week or so, the responsibilities of four children at home made it impossible for me to stay longer. I phoned her every day and spoke to the nursing staff also, but it was a fretful time for me as I wanted to be in two places at once. Fortunately my brother lives near her, but I still felt bad that the burden of care was all on him.
Luckily, my two sisters-in-law live also near to their parents, so when we do go East to visit, we get to see almost the entire clan.
My mother is old but online , so we keep in touch that way on almost a daily basis (cheaper than phone).
We haven't lived closer than 2-1/2 hours to our families since we've been married, though, so we're used to driving. And my kids laugh at friends who think that the 5 hour drive to "UpNorth" Michigan is a long trip. They've been doing the 12-1/2 hours from infancy.
outnfree