I figured it out. The big starter wire is always hot and connects directly to the battery or battery side of the ford starter solenoid. Medium wire (which attaches to the same place on the starter) I believe was for powering the electrical system on the car as it is also always hot. The smallest wire is the trigger wire and connects to the other terminal on the starter solenoid. I got it to turn over which was a huge relief because I was worried some water could have gotten in the engine and rusted the rings. Pulled everything back out (hopefully for the last time) to reinstall the bolt that engages the spring on the starter and install the tach sensor that came with my Dakota Digital kit (any tips on setting it up would be much appreciated). Hopefully will have a break from homework this weekend to finish off those couple things and start resembling the truck!