Alternator shorted out and speedo and tach quit

They aren't related to the alternator unless a fuse blew. The Engine Computer sends a digital signal to the Body Computer which interprets it and sends another digital signal to the instrument cluster which is a computer module itself. Typically if only one or two gauges don't work, it's a problem in the instrument cluster. If the gauges work but stay on "0", it can be a problem in any of those computers.

If the transmission shifts properly, you know the speed sensors, Engine Computer, and Transmission Computer are working properly.

Where are you? There's a real nice chain of about two dozen very clean and well-organized yards called "Pull-A-Part" between Ohio and southern Georgia. I've been to 16 of them. A 2002 is a little new for them. On my last visit two years ago, the newest I saw was a '98 Caravan. You can do an internet search to check their inventory at each yard.