how did you come to know your timing chain is out? TDC'd the engine? engine cranks but the valve train doesn't move? ???
it's not that bad to do a timing chain in a windstar. Book time is about 7 hrs. for timing chain. plus parts, oil change, coolant, probably should do a new water pump and drive belt while they're off. If regular maintenance
has been kept up on the vehicle there would be no reason to believe that there would be damage to other components. Unless you have like a million miles or so. (Ok, maybe not a million but at least a lot more than normal miles for a vehicle that is 12 years old) If everything else on the van is good I would fix it. If it is getting beat up and has a lot of miles I might consider getting a newer vehicle but you would have to weigh the price of a new car or how much you would pay for a used car and what do you know about how that car was cared for.