1992 Ford Aerostar. Radiator/Cooling issue?

I just got this van knowing it needed a radiator. When I went to get a flush to see if that'd fix it. STS said they couldn't flush it because it was clogged with rust. I was also clogged the water pump. Basically everything needed to be replaced. They did not charge me, and gave me a guess of around $1000.00.
Does this seem right? The price? That a flush will not fix the problem? And that everything needs to be replaced?

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