is this 69 dart a decent price?

Good price even with a rear window that needs to be replaced witch he has for you.
Yes, check it out even if you have to use a mirror, But I am sure he won't mind you looking at it under it, If you have a small floor jack I would bring it with you..
That is a p/s car and a great year model, keep us updated and double check the vin# against the tittle.