Wondering if anybody has used synthetic trans. fluid in their van when changing the fluid. Would like to try it being the transmissions on these vans are there weak points.

As long as it says something about being compatible with Honda ATF-Z1, I'd use it. Drain/fills are easy enough on the 5spd autos. Also, don't forget you do have a filter on your 2004:
http://i85.photobucket.com/albums/k65/mtpockets06/99thru04OdyTrans.jpg
Joel