Is the long hard line that runs under the radiator needed. This is the return line from the gearbox to the power steering pump. Can just run a short piece of rubber hose.

 

Sure you can do that.

Expect your fluid to overheat and your steering to work like crap if at all and all your seals and stuff to fail as a result and to have to deal with leaks and various other failure as a consequence of this "improvement".

That's your PS fluid cooler.

 

It's not quite that bad. Yes, it is the power steering cooler. It's not absolutely necessary, I've run without it for a while trying to diagnose some power steering problems and I honestly didn't see any difference in everyday driving in warm weather (60's-80's).

If it's rotted out or otherwise messed up you can bypass it temporarily, but I would replace it with a new loop or some other cooler eventually. The fluid will wear out faster, it will cook the seals in the power steering assembly eventually, and I wouldn't be surprised to see it boiling over in an autox or road race type situation (this was a very common problem with 4th gens)