Sediment broken free in pipes has likely caused lower water pressure
Had some good success getting the pressure up a bit. It's not back to where it was but it's manageable at the moment.
Changing the main valve that comes into the house helped a lot. It was so corroded that it wasn't opening up all the way and it obviously wasn't closing all the way either. I changed that to a ball valve style shut off and I cleaned out the aerators on all the faucets and the shower. I removed the shower head and it shot a good amount of gunk into the tub. Almost looked like someone was panning for gold in the tub. Got all that cleaned up and soaked everything in CLR overnight and I'd say the pressure is at about 75% of what it was. I still think I'm going to try the backflow deal from the shower and purge it outside and see if that helps get it back to where it was.
One problem I have is I can't change all of the galvanized pipes and connectors outside because they are so corroded I can't get them apart. If I break the pipe going into the house I'm going to be in deep **** so hopefully I can get it back to where it was without dicking around with that.