Need a quote for my 69 mustang?
It likely has 105,216 miles, not 5216. No way the engine, transmission, and axle would all require rebuilds with only 5k on the clock.
This car is going to require at least $10k in repairs, probably closer to $15k before it gets back into presentably condition. New/rebuilt engine, new/rebuilt transmission, new/rebuilt axle, new paint, emblems, new fender possible, new tires, new windshield, new dash, and I'm sure there are a couple things as well.
You didn't mention what model or bodystyle or engine or what transmission it has and those things figure heavily into the value of the car. A Boss 429 is worth a hell of alot more than a base notch with the straight 6.
For a non running notch with an I6, or a 302, $2500-$3000 sounds about right, it's not worth a hell of alot as it sits. The value you got from NADA is for a mechanically sound car, this one is not mechanically sound.