[1966conv]

Rusty floor pan sometimes indicates that the cowl may be leaking. That could be a big unknown. The other stuff is relatively minor. If the car is close to what you stated, somewhere between $2K to $4K depending on the cowl condition. When, or if, has the engine/heads been rebuilt +-$500 to $1000. A little more detail could maybe get a closer price for you.
A way to check your cowls is to pour water into them and see if it leaks inside to the carpet and floorpan.

1966 Red Conv (200)
1966 White Pony Int.(289)A Code
1966 Coupe (289) C Code
MCA 36048

 

[1966conv]

In that case, you're talking about $1200 to $2000 to professionally fix the cowl's. Sometime the engine will have to be rebuilt $350+ for the head, Bottom end intangible, having never had a rebuild.
My .02c puts the car between $1000 and $1500. Obviously has more sentimental value to family. You could easily spend $3000 or more at the blink of an eye here. Look on ebay, coupes are not really bring that much.

1966 Red Conv (200)
1966 White Pony Int.(289)A Code
1966 Coupe (289) C Code
MCA 36048