Congrats on getting some time to put it back together!
Well, at least your switch side of the circuit is working on the starter, getting the buzzing solenoid. Have you rapped on the solenoid with a screw driver handle to see if it is sticking?
Check your voltage on the solenoid to see if you have battery voltage there and compare to your battery reading. Direct shorting the terminals on the solenoid, does that cause it to work correctly?
Thanks!
David