We have two in college who are about that distance away (8 hour drive); our youngest will be about as far when she starts college in the fall. Whether you drive or fly, this is too far for a day trip. With that in mind, our typical pattern has been to see each kid once for a weekend visit sometime in October. Sometimes we've gone up for families weekend or to see them in a game; their school has a fall break, and sometimes we've actually gone up that weekend. I think one of them came home once in the fall for a family wedding.
In the second semester, we usually go up to visit for a weekend sometime before spring break. As other posters have commented, kids usually appreciate going out to dinner, and maybe going for a hike or to visit a museum. We might make a run to Target or something like that. Otherwise, we're quite capable of entertaining ourselves, so we're not cramping their style or getting in the way of their doing school work. We have friends who live in the area, so sometimes we get together with them.
I think we actually spent part of one spring break with one kid, but, otherwise, schedules haven't worked out for us to be together, so the kids have done spring break trips with their friends or cousins -- sometimes service trips and other times just for fun. Oh, and, when the oldest studied abroad, I spent a long weekend with him in London. The middle kid will study abroad this year, and DH will travel to see him.
We're a close-knit family, and enjoy spending time together, so we make the effort and spend the money to see them. And, it doesn't seem to have warped them in any way -- they're pretty independent -- they've had summer internships and jobs away from home every summer after the first year, and the oldest will be going to med school in a fabulous city that's a 2 hour flight away. We're looking forward to visiting him there. (And, TBH, we're looking forward to having an empty nest -- so I guess we haven't been warped either.

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