Welcome to the pool.

It would be very difficult to tell you ALL the things you need to look for. At 9 grand the car could be a screamin' deal, or a screamin' nightmare. Be carefull of one thing right off the bat. When comparing to other rods on the market, comparing the price of a Ford against everything else doesn't work. Fords just bring more money because of higher demand (within the years you've mentioned). Plymouths will usually be less valuable than Chevrolets. Yeah, it may defy logic if you just think of them as old tin, but market forces play a part.

Next, make sure you REALLY like the car. Many have bought down to a price rather than up to what they really want and have later regretted it. That is, unless you've just got so much money it doesn't matter if you make a mistake. Most people find mechanical issues to be easier to deal with than body, paint, upholstery, etc. Wheels and tires are easily changed. In part it depends on what your real skills are. If you're a journeyman body tech, then body work becomes easy, and maybe mechanical is more difficult. Assess your REAL skills and judge accordingly. Some will rationalize buying a messed up car "for the opportunity to learn". Great. If you've got the mechanical apptitude, and have grasped manual tasks in challenging areas your entire life with ease, you're a good candidate for that type of deal. If most of your car building skills have been in your dreams, then it could be a daunting task that will only teach you that you should have pursued stamps as a hobby.

Check the body over everywhere. Be especially mindfull of creases, folds, nooks and crannies. The tin worm (rust) lives in all of those. Any rust through you can see is less than there is. For example, if you're looking at a rust hole the size of a quarter, you'll have to cut out almost three times that to get to solid metal that will take a weld. If it's painted and the paint has "bubbles", particularly in the areas listed above, that's rust, not a paint problem as most sellers would like you to believe. Just 'cause you can't see through it doesn't mean it's not rusted through anyway. If you've never done rust repair, or any body work for that matter, it's tougher than it looks. If you have to pay a pro to fix those things it can cost a ton. Most body guys I know HATE doing rust repair....................there's a clue there.

When you say "Mustang parts" I assume you mean it's got a Mustang II front suspension. Done right it could be good, done wrong, mucho problemo. First thing, stand well back from the car on both sides. See if the wheel/tire on the front, and back for that matter, are "centered" in the wheel opening visually. This is a little hard to convey in words, but that doesn't necessarily mean perfectly centered if measured with a tape. The curve of the wheel opening may be an elipse rather than a perfect "half" circle. In that case it has to look "right". If it doesn't look balanced in the opening then the suspension was installed in the wrong place. Fixing the rear usually is fairly easy depending on what was done wrong. But fixing the front means undoing the improperly welded in stuff, maybe throwing it away depending on how they botched it, and then going through the whole process of reinstalling it right.

If the car's driveable be very tuned in on the handling. Not so much how it goes around corners, unless it does some unusual bucking or groaning, but moreso how it steers over irregular pavement. Such as, speed bumps, pot holes, man hole covers, driveway aprons, etc. If it gets "darty" or pulls hard, the suspension is in wrong. Sometimes it's a simple tie rod fix, often times with a front suspension transfer somethings in the wrong place. Major fix again.

If the body and suspension are solid then it all depends on what you're after for style. If you want the car to look fairly stock in trim and shape, then make sure it's already got all the "little" pieces. You start buying dash trim, gauge panels, door handles, latches, exterior handles, hood ornaments, bumper guards, and all the rest of those type items a bit here and a bit there, and it adds up in a hot hurry. If you're going to do a beater style car (what some people call rat rods), then it's whatever you can live with. The same for any other variation, judge accordingly.

This pretty much scratches the surface, but the body and suspension can be back breakers so that's why I would focus on those. What would be better is for you to treat this like any other endeavor in life. Learn first, then jump in. If you hung around with experienced rodders, looked at what they've done, asked a bunch of questions, learned what's involved in repairing each aspect of the car, you'd increase your chances of enjoying the process. Or you can do like a lot of us did...........learn by digging out. It ain't all bad, it just depends on how you tick and what you can afford.