What should I check?

I'm thinking about buying a Dodge Durango 2003 (with the infamous 4.7L). Also, the Durango has 57K miles. I've read through this forum and got some real good data about how to flush out the sludge using: Kerosene or Rislone. Also, I found the Mobil 1 discussion really interesting.

The seller (over the phone) said that the "frame is cracked or bent". He says that a previous prospective buyer said that "the thingy was bent and or cracked". I've got a appointment at the dealer to find out what the thingy actually is.

Can you guys give me any problem areas to look at when I go out to look at it?

Thanks,
Stan