Just a hint about being tired and still getting your
workout in.... will you have time to get the
workout out of the way early in the morning before work? That works for a lot of people. You do it first while you still have the energy....
For me, regardless of the time of day and what my schedule has in store for me, the hardest part of my workout is getting to the gym. After I am there, its no sweat!
Good luck and stay at it!