My grandparents' health is declining, and I'm not sure how much more I'll get to see them.

My grandfather had a stroke 6-7 years ago, and has had some minor ones since. In the last month, he's fallen several times.

He's still doing OK mentally (though I think one of the recent falls was a head blow, which affected his speech a bit), but obviously not so much physically.
My grandmother has Alzheimer's.

She's not so hot physically, either (bad knees/hips). Mentally she's mostly still "with it" (she knows who people are, and what happened last week, but not necessarily what she did/said last hour), but I don't know how long that will last.
I'm looking into adding a leg to my Thanksgiving trip to go see them. I was hoping to put that off until next summer, since the trip already involves 2 legs (and coasts), and I don't really fancy MI in the winter, but oh well. I just hope they're still in semi-decent shape by then.