Interior appears to be better condition than exterior shows. Factor in complete respray, it's been sprayed a few times already and current paint is trashed. Even if engine was ok it's now been sitting so long that it is probably dry and needs new gaskets etc so also factor in a rebuild cost. It might be a great project, but they are often worth less than they think. They didn't care enough to cover it up so obviously little value in their minds, except when selling. Consider it a parts car, as mentioned and pay for it accordingly, with the view to decide if it's a suitable candidate to use as base or not.
