Actually...when so many lights go out concurrently, I think the problem is easier to solve. You just have to find the common denominator which may be a fuse, a connector at the headlight or ignition switch or a common ground lost. If you don’t have the wiring diagram book you can usually find one on line by searching images. Many of the various years of Ford trucks are similar. Of course, if someone “customized” your wiring, it may not match the diagram.

A lot of stuff goes through the firewall, those rubber block and SAE bullet connectors. Soak them for a day or two with penetrating fluid so the pins draw in the juice, before trying to pull them apart, if they haven't been cleaned up for a while. Anywhere on the truck there's a connection, it will have a huge voltage drop by now if it even works at all. Treat them electrons with respect, son!

Basically every single ground & electrical connector on that thing is suspect, no, make that convicted, if it hasn't been cracked open and cleaned up. Wire bristle brush and some kerosene will shine up the pins and receptacles, also clean up the battery, starter and block to frame ground points to bright metal etc. Doesn't cost a thing except for some of your time. Resonateur is right, the more lights and major stuff that is completely inop, the easier it will be to find. You'll be glad you took the time to do a little preventive maintenance, it affects everything from hard starting and poor charging and strange electrical faults in the future, it ain't no fun and it's dangerous troubleshooting on the side of the road.