Just changed the coolant on Saturday. Have a '97 w/ the 5.4 and 4x4. There is a pet**** at the bottom passenger side of the radiator. Best access was from the right front passenger wheel well, slightly hidden behind the wheel splash protection.
What I did -
Open the radiator cap on the degas bottle.
Open the pet**** on the radiator and drain into a bucket.
Close pet****, poor in distilled water into radiator slowly.
Replace radiator cap.
Start truck, turn heater on high and let cycle for a few min after thermostat opens up.
Drain radiator again per same as above, make sure about pressure on rad cap.
Overall, I drain the radiator 3 times.
After the last drain, I fill with 100% anti-freeze.
Drive it around for awhile, check strength and adjust when filling to the proper cold level after truck cools.
Using distilled water is better for the radiator. Also running your truck with 100% distilled water for a bit will clean the coolant system (distilled water is a good cleaner for it). Draining the radiator is about 1/2 of the coolant in the vehicle, so it works out pretty good. Also, you are not dumping it into the drain.