Have you looked into a Toyota Sienna? The Dodge Grand Caravan is a horrible minivan and that generation of Odyssey you are contemplating to buy is known for its electrical issues let alone weak transmission and on top of that power steering issues. I would avoid both. 

Between those two I would definitely go with the Odyssey. Odysseys have their issues but they are still way better than Caravans.

Whatever you do, make sure you do not get any Dodge or Chrysler made minivan - they’re awful. I would go for a Toyota Sienna. They’re the gold standard. 

Dodge Caravan is the worst minivan you possibly could get. Honda Odysseys have hectic issues, but not as worst as Dodge. Look for the Toyota Sienna first before making your decision. If I have to choose either the two, I would choose Honda because of how comfortable the seats are and how they drive. 

The newer Honda Odyssey’s are not as good, and forget about the Dodge Caravans.  If I were in your shoes, I would look at a Toyota Sienna instead.

I would look at later model Odyssey vans since they ironed out their transmission issues, don't buy the Grand Caravans since they are piles of junk. You can also consider a Sienna, those are great Minivans. My dad drives a 2016 odyssey and it runs like a dream. I would go Odyssey or Sienna.