I'm new here, but will toss my opinion in as well. I have been in body repair for 35 years and today all I do is classic cars.
First of all, Let's forget about the "anchor to a tree" idea. That is how we straighten demolition derby cars to run one more time. It works, but not very accurate.
Secondly, a come along would probably break and then we would be discussing how to fix a different type of body all together! Hydraulics and a digital frame rack is the way to go. The floor pots work, but again, accuracy and multiple simultaneous pulls (recreating the collision in reverse) would be key in dealing with something this severe.
I would also like to add that the "it'll never be the same" adage is incorrect. I tell my customers that if you can tell where I made any repair, if it drives differently, squeaks, rattles or dose anything that it did not do before the collision the repairs will be free of charge. The whole point is to return to pre-collision condition or better. It's not years of experience, it's caring about quality and a love for all things on wheels!
Now, all that said, if I were to repair this car (I say "if" to stay on topic) I would take JohnD1956's advice and use it as a donor for another car. However, if the car has a significant or sentimental attachment to you repair it, I always say anything can be repaired, the question is should it be?