Ford Repair: ford electrical problem, altenator, electrical problem

Question
i own a 1986 ford f150, 2 wheel drive with a 300 straight 6. and a while ago i went to start it and i couldnt get power to anything. after tinkering with it for almost a year now the only way i could get it to start or even crank was to run a wire from the battery to the headlight and turn the headlight switch on and sure enough it started.  i know i have a major electrical problem, i also had my altenater tested and it failed, but i am skeptical that the altenator is the problem, could that be it?  i really dont want to give up on it because the motor still runs strong. any help you could give me would be very much appreciated, thank you for your time.

Answer
Short of coming to your location, it will be hard for me to tell you where to start. First you mentioned no power anywhere, but the headlamps work. So is it no power anywhere, or the engine won't crank?

Depending on your answer to this question then I can offer some advice. The year of your truck is one that had problems with the igntion switch, if it is a starting problem then I would begin with the switch.