I went that way last summer. Do you have your EZ Pass? Going up 95 wasn't bad just jog over and use the Tappan Zee and not the Gorge Washington. GW cost me $76.00. I have driven 95 around Boston and 495 I didn't see any difference in traffic. Yes it is best not to do it during rush hour.
It depends on what you want to do and see around Portland and north. 295 and 95 split but come back together. If you are going to Acadia I would use 295 to 1 and follow 1 to 3 to the park. Where are you staying? I drove 1 all the way to East Port.
Bill