Remove any zip ties you have installed...they may be hiding wires that have been chewed at by mice etc and being all tied up in a bundle will make it impossible to diagnose.
First thing to check is fusible link in system to see if its shorted out and burned up....
Then check battery voltage
Battery leads to starter tight
Battery ground clean and tight
Ground cable between engine and cab in place
Ground cable engine to chassis in place
Check these and report back...then we will get into the wiring system for the ignition and start circuits...
