How can I stop the truck from shutting down from idling bumping cruise up doesn't work

I researched these codes and found the following suggestions.Has your vehicle gone into limp mode (i.e.-check engine light is on &/or vehicle isn't making its normal power output??) Check your transmission fluid with the engine warm and at idle and if it's low,fill it to the appropriate level.P0700 is normally set when the tcm detects a fault.This is a common fault code in this model.Low/dirty transmission fluid can cause two sensors inside the transmission to short out requiring you to replace them.P0571 is related to the brake/cruise control switch, which is connected to your brake pedal.This operates your brake lights and deactivates the cruise control when you step on the brake pedal to slow down/stop.Have someone verify your brake lights are working and also make sure they're not remaining on after the pedal is released as non functioning brake lights could cause an accident.If your cruise control is working,verify it is shutting off when you press the brake pedal down.If it's not shutting off,that could also be dangerous too just like no brake lights.If it's not shutting off,check the switch to make sure it hasn't been knocked loose from the pedal and check the wiring harness also to make sure it's still connected.Check any fuse for the cruise control and brake lights also.
If the transmission fluid is low and you top it off and if you correct any condition present with the cruise/brake light switch,clear the codes with a scanner or get AutoZone/Etc to do it for free to see if the codes clear and remain that way.

Try by checking the cruise control relay as well as the fuses.The relay may be getting hot and shutting down.

the sensor at the propshaft area sounds like its loose or defective

When it shuts off at idle, can you still hear the humming of the fuel pump?

going down steep hills will all but over ride a cruise control, since the motor is trying to keep the vehicle slowed to what your desired speed that you set , unfortunately this doesn't always work,, as your speed increases, the motor can't keep the speed reduced, when you apply the brakes, the system shuts off, cruise controls were meant to be used pretty much on long flat surfaces with Low inclines ,,

SOUND LIKE THE FUEL PUMP.CHECK FUEL PRESSURE SHOULD BE 34 PSI AT IDLE. WITH NEW FUEL FILTER.

I don't think they are related

could be the module behind the airbag

The coolant temp sensor sends signal to the ECU and the ECU adjusts the idle RPM. When the coolant is cold, the engine requires more fuel to sustain idle with thick oil (oil gets thicker & more viscous when cold). This makes the engine to idle at faster RPM but it should settle down to 850 RPM or so after the coolant warms up. The sensor is nothing but a thermistor; a device that changes electrical resistance according to the coolant temperature.