Is it possible to just heavily load the back of the truck and then put a jack under the bent point and just jack up? I've used the weight of my truck for this kind of thing before, put a block under the bent point and then drive the front of my cummins up on it, 4tons is a lot of bending force.
Otherwise the angle grinder is the way to go, you'll cut through it all in about 10 min. If it was me... my 50A plasma will go through that in about a minute...
