My concrete garage floor is at least 40 years old. The garage is unheated, cinderblock construction. The concrete floor is worn down and breakup up on the outside 2 foot perimeter of the floor. The entire floor is 13'9" x 22'10". What would be the best method to repair this floor to make it one strong, durable, no cracked, level surface

Power wash and clean the entire garage surface, spread a liquid binder on the existing surface (this will bind the old concrete to the new) then you can trowel down concrete resurfacing cement.

Resurfacing concrete mix can be spread from a skim coat up to a 1/4" thick if I remember correctly.

I don't know where you live but if your in a snowy area avoid getting rock salt on any part of the concrete.