I never understood the idea of getting to your spot 2 hours before first light. In addition to the points you raised, here are a few:
1.) Deer walk by and you can't shoot
2.) You are more likely to end your hunt early due to being cold if you're already sitting in the woods for 2 hours before you can see.
3.) You are more likely to end your hunt early due to being bored if you're already sitting in the woods for 2 hours before you can see.
4.) You will be hungry or have to go potty earlier in your hunt.
Plus, what time are you waking up? 3:00am? Might be better to get some more sleep so you are alert.
I say get in there 15-30 minutes before light is fine.