You won't be able to see exactly what you see in this photo with just your eyes, even if the moon is not out and you are in the deepest & darkest part of Maine.

If you want to see as many stars and planets in the sky as you can in Maine, go out a few hours after sunset or before sunrise where there is little to no light pollution, https://www.lightpollutionmap.info, and no full moon or moon is not out.

Yes that's plenty of time. PWM is my home airport and the longest line I've ever encountered is the one to check bags in. From when I enter the airport from outside, check bags, go through security is 10-20 minutes. I do have TSA PreCheck but almost never see a line longer than 10 people and that goes quick.

I used to fly out of BOS, that's a whole different animal...