As others have stated... service records. Probably worth pulling service bulletins just to be aware of things to look for. If equipped with DVD player, make sure it works (the player on our 08 SLT failed fast). Welcome!
While I loved all 3 off my Acadias, it's not a car i would be comfortable owning after 100k.
I'm not saying that it's going to die at 101k by any means, but you're definitely more likely to get some high-cost repairs after that compared to some other brands.
I assume you're looking at an 08 with 165k because of the price but I would imagine the cost of the repairs in the first few years would be more than you'd spend on a better car, I would much rather suggest a lower mile car or get a Honda Odyssey