If your hoses are that hot, chances are your heater core is filthy, missing fins, and/or plugged inside. Or a combo of all of these. The only true solution would be to replace it. Now, that being said, I do believe with the engine at operating temp the coolant in those hoses should be about 200 degrees - rubber isn't really a great heat conductor, so maybe put a sensor on the thermostat housing. One thing I have an issue with mine, is that I have a GARBAGE A/M thermostat in and I never get to operating temp in the winter because the thing doesn't close fully.