So... Gauge read 250 but rubber hoses were cold?

At 250 it should be painful to touch the hoses.

Pull the radiator out of the car. Use a garden hose at full blast, and see if the radiator can flow enough to not back up. If the radiator can flow the 5 gallons per minute that a garden hose can put out, then you have enough flow to heat up the upper radiator hose.

So if your upper hose is not hot when the gauge reads 250, and the radiator is not plugged, then you either have a faulty gauge issue or a thermostat that's not opening.

You can test water pump flow by disconnecting the upper hose at the radiator and removing the thermostat. Water should flow out of the upper hose.