I can usually only nap Fri or Sat since I don't have to worry about what time I go to bed (I could nap after work - around 4pm - but that would mean I would go to bed way later and have a hard time falling asleep).
The only caffeine I get is in my preworkout first thing in the morning. My workouts are around 6-7:30 am. I don't drink coffee/tea/pop after that (just H2O and milk).
I've read that overtraining can affect your sleep. The thing is that I don't feel like I'm overtraining. I don't feel down, depressed, lethargy, unmotivated, etc.