They really don't have weak points other than rust. And that would be the typical places on the fenders and across the front of the hood. ANother place is look in the cowl vent and down towards the door hinges is a bad place they rust and VERY hard to fix.
Pictures aren't the best in the ad, although he's been very good communicating over text messages. Sent me the undercarriage photos pretty quickly. It'll be a long-ish drive, but I think worth it.