Radiator is out, what can I do in the meantime?

66 dart L6 3.7L, 225 .
Removed rad. It still has some original metal tags on it from the Radiator shop who built it? In Los Angeles.
Dropped off the rad. and will be tested and see if it is possible to fix.
BTW: Spectra Premium CU 517 seems to be the closest fit to my orig. Same 6in TOC spacing. Mounting holes probably have to be redrilled. At least upper mounting holes are within 1/2in of the orig.

So since rad. is out, I would like to do some other rehabs. like new belts, and also new thermostat and hoses. Is it worth my time and water to attempt to flush out the Engine cooling inlet/outlet? Stick a hose and turn it on?

Any other ideas? Temperature sensor?