Last year, right around Christmas time we got walloped with 3 feet of heavy snow in the Rockland area. I have a Tacoma 4X4 and barely got out of the driveway. Myself and and my boss were the only two (of the 25 scheduled) to make it in to open the store. Those storms aren't the norm though.
I've spent some time all over the country including Missouri as a long-haul trucker for twelve years, I've seen it all. MO's weather is a bit nicer and milder but Maine's weather should be no problem at all for ya.
Our weather is easy, getting a CWP from Portland's new police chief may be much more difficult. I've never applied for a CWP so I'm not sure of the process...County Sheriff's Office, City Police Department, or State Police. Google would be your friend there. Our local media is rabidly liberal and may print your name and address in their local rag, they've done it in the past in Waldo County; man that pissed me off.
As far as Maine's Second Amendment rights go we are still the freeest of the free states. Don't let Connecticut and Massachusetts scare you. Our police forces (except maybe Portland's new Chief) are really middle of the road and professional.
Eateries...hhmmm...I've had good luck with DeMillo's Floating Restaurant and the always popular Macaroni Grill. I grew up in Waldo County so if your traveling up Rt. 1 stop into Angler's in Searsport. Huge portions and great food.
Parking in the city during storms and during cleanup is a Portland sport. The local television stations broadcast parking bans ahead of time and get your car off the street or you'll spend a fortune getting it out of impound. Again, never lived in Portland but have watched Channel 6 for 40 years.
Ranges around Maine are really scarce in general. Most locals drive long distances to private club ranges, beg gravel pit owners for access, endlessly seek that elusive perfect place, or live on a big and remote enough piece of land to have their own privte range. Best advice I have in finding a range or a place to shoot and the CWP process is to talk with the local gun shop.
Welcome to Maine.