All F150's from at least 97-03 are wired for trailer towing from the fuse box back to the back of the truck..... They will all have the brake controller connector under the dash (just above where your right leg is when you sit in the drivers seat) as well.
The difference is when you DON'T get the tow package, you don't get the two relays and the 30 amp fuse that plug into the fuse boxes under the hood. I think there is also another fuse for the trailer lights as well. You also only get a flat 4 trailer connector, as all F150's are capable of towing using the bumper hitch if you add a ball to it.
So, all you need is to get the fuses and relays and then get the factory round 7 pin connector and it'll plug into the factory wiring harness right around where the spare tire is. It replaces the harness that goes to the old flat 4. You will also need to get the brake controller "pig tail" harness for the brake controller connector under the dash. This is what you would splice to the connector that comes with the controller. Some controllers have pre wired connectors that will plug into the truck and controller in one shot. That's the easiest way to do it.....
The relays only control the 12v charge line to the trailers battery and reverse lights if your trailer has them.
Then you'll need a frame mounted hitch receiver and check to see if your truck has an aux tranny cooler.