Is it normal in these vans to here the fuel pump humming? I hear it when I turn the key on and while I am driving. It never gets quiet.

 

It should run for 2 seconds when you first switch the key to the ON position. On mine, it's quiet enough that I usually don't hear it. If it's loud enough to hear over road noise, it could be wearing out, ready to fail.

Is it a constant whine, or is it irregular? If the latter, it's more evidence that it's on the way out.

 

It is a constant whine while driving.

 

Replace the fuel filter, it means that either the pump is about ready to fail, or it is working hard all the time. There are only a handful of replacement pumps I've found to work with any degree of success, especially if you define success as the ability to drive long distances in hot weather without failure. You need either Genuine Motorcraft, a genuine Carter (not an Airtex or generic one in a Carter box), Walbro, and possibly Standard.