What the comments above are saying is that you need to determine if the structural part of the car, the frame underneath, is weakened by rust. If it is, then it is not safe and should be avoided. This should be especially relevant to you after the crash you mentioned and what happened to the Blazer.
Making the determination about the structural integrity of the frame takes probing around underneath, preferably by someone who knows what they are doing, ideally a body shop as someone mentioned… Even then, it may be impossible to really judge it adequately. But what you’ve said so far about the Pathfinder in question raises caution flags, especially proximity to the ocean and beach driving, which I presume means running the thing into salt water. That means rust damage is more likely.
Since you are looking for something for just a short time, I think you’d be wise to look first for how well a vehicle has been maintained, and then by the resale value. You’ll lose a ton of money buying a rusty Pathfinder from a dealer. In contrast, you’ll do much much better financially by buying a dull little sedan that’s been carefully maintained by someone who is selling privately and can give you all the maintenance records. You may not lose much at all if you only own it for a few months.
In all cases, take the car to a trustworthy mechanic for evaluation as several people have said, and budget $100 for that. And pay particular attention to what maintenance the transmission has had. Those should have been serviced roughly every 30 thousand miles. If you find a car with something like that kind of maintenance, it may be your best choice.
I’m a Nissan fan, and recently was intrigued by the idea of getting an older Pathfinder to replace my worn out Nissan pickup. Never did get one though…