Update:  So, an update as to what I have done.  1st attempt was a tire/wheel/springs/hanger upgrade.  I went with new wheels and tires.  Went up to "D" range tires and 15 inch rims.  Still on 5 lug wheels.  I upgraded to 2550# springs and Dexter's heavy duty equalizer kit.  That went well except that I actually had a bent axle.  My passenger side front tires was out a little at the bottom and pulled in on the top.  I thought it was something wrong with my install, but no....the axle was bent.   I have now purchased 2 new 3500# axles and installed them.  Everything looks straight now.   We'll see.  The only thing I can think is that when I had my blowout last summer, the sudden drop was too much for the remaining axle and it bent it.   It's was the axle that didn't blow a tire.  Anyone ever seen that before?  Again, trailer weighs 6400# on the 2 axles.
Thoughts?