I would think that any place the sells trailer stuff would likely have something that would work. Not sure about the washers though.

 

I found one place & I hope this washer will fit & be thick enough to handle the weight. It's the only place I found that has a 1" keyed spindle washer. It's very difficult to find this washer. It's also getting difficult to find a 1998 Dodge Ram 2500 Cummins 12 valve RWD at the pick-a-part places. I appreciate the part #'s given, specs, & suggestions. Here's the link to the washer I found.
https://www.etrailer.com/p-165863.html
I also found a salvage place 50 miles away that recently received a truck like mine & it has the parts I need, so I'm going there in the morning. I've always said I will drive my truck til the wheels fall off. I'm lucky my wheel didn't fall off. (I was driving 40mph when I suddenly heard the chirping & growling from the wheel & slowed down to 30mph & less) I'm determined to keep the wheels on it because it's just now getting broken in at 435,000 miles....plus I love my truck! Thanks again everyone!