I think you've got a $1500 914 all day long! The front trunk has a few spots, the front of driver's rear quarter at the bottom looks a little "bondo sketchy", and it obviously needs some bodywork. That said, as far as 50 year old hell holes goes, yours looks pretty damn good. The floor pans look like they've already been addressed, and the rear trunk looks pretty good.
The longs are a bit suspicious, but honestly, that could go either way. To me it looks like the inner longs have a stiffening kit, and another poster says the outside is also a stiffening kit. I find it unlikely that someone would go to the trouble of addressing the inside and outside of the longs, just to leave the insides a rusty mess. Personally, I could care less if the jacking point is there....although, if it bothers you, it looks like he has included a set in the sale. My point here is that if you're buying this to make it into an autocrosser or nice driver quality vehicle, this whole "long" issue might be a good thing. It could be stiffer than stock. I guess you'd need a camera in there to really know.
The other places I would like to see are behind the back pad AND pictures from underneath the car...doughnut holes, suspension, trailing arms, etc. It's 4 screws to remove the pad and unscrewing the engine lid latch. The bottoms of the firewall behind the seat are often rusted. It would be nice to see the condition of those lower firewall corners.
If you're interested in a future concours car, this is likely not it. If you want to upgrade the suspension, engine, and create your version of the 914, I think this is a great place to start. Good Luck!