+1 for Keith, If the end rail is bent or the car is slighted tweak, you can pull it out with a port-power or chains. I have been down this path on a few cars. At my dads shop and my shop when we poured the concrete floor, we made anchors in my floor to do such work. The key is to measure and measure everything. There are books that have the specifications. I have pulled several cars and once I was done, I took them a alignment rack to verify the work, and we done it correctly and the wheels didnt even need to be aligned.
It can be done on a budget, if you dont have the tools, take to frame shop.