The best way that i know to check the radiator hose, without taking them off, is to squeeze them between your thumb & fingers in the curved part, if you feel a sort of crunching, that means the springs are rusted & not able to keep the hose from collapsing, this would cause rusting in the radiator itself & likely cause the thermostat to malfunction
the heater is a different matter, there could be several reasons for failure in the heating system.
First thing to check is the water flow
drive the truck, both hoses should be the same hot temperature, if they are not
don't pull the heater hoses off at the firewall, you can see that access to that area is sort of tightly restricted.
Pull the hose clamps off close to the water pump end of the hoses, try running water or air pressure through the hoses & heater, you may need to open the heater controls to get flow, i don't think that the fan has to be on.
If you seem to have a good flow, you likely have an issue with the different heater doors or vents, or possibly a little motor
Then it is time to go online & watch 3 videos on youtube