With a thorough inspection, inside out , and upside down , if things looked good overall , I would drive the hell out of that.
Price will change depending on location.
My guess would be around 15k , I would be prepared to spend another few thousand for unseen issues.
But hard to price one offs.
May be you will find the person that has been searching for something just like this. And you can pull 25k.
B I would do all I could to put it out there , the more that see it , someone will have to have.
I would wait to discuss price until I see their body language, then set cost at how bad they want it.