Just replaced mine the other day.
The upper hose is a pain to remove, you have to really wiggle it too get it off.
Good thing that you ordered a transmission thermostat I broke mine getting tank out.
I also picked up a new cap.
Somebody on the group mentioned about using a old cap to pry the tank out. Put a large screw driver under lip of cap and it pop right off.
Changed out water pump, thermostat and all the belts at 91K about a month ago. Cheap me didn't want to spend the money at the time for a new tank. The old saying "Pay me now or pay me a lot more later" which was for anti freeze.