What's it Worth? Seeking rough valuation on manual 1967 Coupe w/ 351 Windsor

I did a quick and dirty look at my favorite pricing tool, the Hagerty pricing guide. (I assume your looking to buy this car, not sell it) It listed a restored 1967 Mustang Coupe with a 289 at $17,800. However, that's for a nice, finished, stock coupe. This one has a 351W (better be sure about that, because they look a LOT like the more common 289/302 unless you know what you're looking at) and a 5 speed (looks like a stock 3 spd./4 spd. shifter to me, but they make ones that look like stock for T5 swaps) so that adds to the value in my opinion. How much? Maybe $1500 extra. It looks like a good start and seems all there. Now for the bad, it's had at least one paint job and they don't appear to have removed the doors or fenders when they did it, so you'll need to either do it for the next repaint or pay someone. Factor in $5k-$10K to pay for that. The hood has been cut up for a scoop, so figure the cost of a nice repro and shipping unless you know of a good original. Also don't forget all the ancillary items that go with a good paint job like weather stripping, door hinge rebuilds, sill plates and all the hood and door bumpers plus door handles since your old ones will look like poop next to new paint. Total for paint and bodywork assuming nothing is hiding below the budget paint on the car: $7K-$15K.
As for the interior, if your looking to make it nice, there's not a lot you can use. Seat covers, carpet, gauge bezel, shift boot, pedal covers (the dash looks good) and door panels can gobble up $1,000 pretty quickly, double that if you need to pay someone or it needs headliner.
Moving on to the mechanical, let's assume the engine is sound and doesn't smoke or knock and likely has been rebuilt (receipts or it didn't happen) at some point in it's life. Judging by the zip-tie holding the gas line, there's likely more than a little sketchiness throughout this car. Assume nothing, verify everything. Does it leak? That's a sign of blow-by caused by worn rings and pistons, or maybe it's just a bad PCV valve ($10). I see it has a non-oem cross-flow radiator, was the car cut up to get it in? Does it leak? Does it overheat after idling along time?
All in all, realize this is THE most common model of all Mustangs ever made. They are everywhere. This is not a car that you are going to flip for a huge Barrett-Jackson style profit. If you love it, it's probably worth $6,000 plus or minus a couple thousand. If you buy it and put $20k into it, you can get $15K out of it when you're done. But if you're looking at it as a fun hobby to play with on the weekends and go to cruise nights and stuff, it looks like a great car. I love these things, but be very careful to know what you're getting into from day 1.