Dodgevity makes a good point about the heater hoses, the heater core tubes are very soft. Usually disconnecting at motor is much easier, especially on taller trucks. If I am changing heater hoses I cut the hose off at the heater core tube, then slit the remaining part of hose and peel it off. Sometimes the hose literally bonds itself to the tube and you have to cut and scrape off the remainder of the hose. On some vehicles the heater hoses are long enough (if in good condition) to reuse the hose that was cut off at the core.