1. I am not sure of this, it depends on your state. Do you need a permit to carry a pistol? If not, then you do not have to provide ID if asked. If you do, it depends on the state. In Minnesota, for example, you must provide your permit and photo ID if requested. This is not true of all states, as far as I know. Handgunlaws.us or a Maine member of this forum would be a better person to ask.
2. Under no circumstances are you ever required to speak to an officer, even if you are arrested. This is the crux of the 5th Amendment to the US Constitution. If you do not want to talk to the officer, you can just say "I do not consent to this encounter." Whether or not you feel comfortable doing that is up to you, but you don't have to talk. If he doesn't let you leave you can just ask if you are detained. If he says no, you can go. If he says yes, ask if you are detained and for what. If you answer a question he asks, that doesn't mean you lose your 5th Amendment rights. You are free to answer or not answer any questions the officer asks.
3. If the officer asks for your firearm, just say "I do not consent to searches." If he attempts to disarm you, do not physically resist. If you do so you can be arrested. You can verbally resist, however.
I hope that helps you, if at least a bit. If you decide to carry a pistol, especially openly, it would be wise to invest in an audio and/or video recorder. They can be had for as little as $10 now and you should have them on if you are carrying a pistol outside of your house, because if you do not have it on before an encounter you may forget to turn it on if an officer approaches you.