My 96 had the front end clunking noise as well. Mine was most easily heard at slow speed any time the van swayed or I stopped or started. It also popped if I moved the wheel side-to-side while stopped. I changed the cradle bushings/sub-frame bushings and it took care of it. They ran about 25 dollars each (4). If you buy some there is a top and bottom for each one. Do one side at a time, and don't have both bolts on one side completely out at the same time.
The Ford mech I spoke to also pointed out that the metal sleeve where the swaybar passes through the front of the frame can come loose and needs to be welded in place. One of mine now makes a bit of noise, mostly heard when I stop and start while backing in and out of the garage.