Photo Equipment: Portland will surprise you with its picturesque setting. Make sure you have your camera to capture the lobsters and the marina and the pleasant streets and the area lighthouses and shoreline and . . .
Luggage and bags: In Maine, the duffle bag and backpack are a must. You will definitely look like a tourist with hard or soft-sided, standard luggage. Portland is laid back---you won't need tons of stuff.
Clothing/Shoes/Weather Gear: Though it is warm (and very humid) in the summer, since Portland is on the ocean, we get the ocean breezes, making a sweatshirt or cardigan sometimes necessary at night. If you travel anytime between fall and spring (mud season), bring cool and warm climate clothing--layers are key. During winter (the snow) and spring (mud season), don't wear shoes/boots that you'll mind getting wet and/or muddy. In the summer, sneakers or sandals are all you'll need. Did I mention Mud Season?
Toiletries and Medical Supplies: The city of Portland is home to several excellent hospitals. You'll never be more than 5 or 10 minutes from one. There are also plenty of drug stores and convenient stores everywhere in case you've forgotten a necessity.
Camping/Beach/Outdoor Gear: Portland is a great 'walk around' city. There are some parks where a blanket and a picnic basket could come in handy. Portland is not far from an abundance of beaches and camp grounds (though you won't be able to swim or pitch a tent in Portland itself).
Luggage and bags: If flying, it is key to pack light. I managed with just a carry on--had no problems. If you plan on buying a lot of souvenirs, you may want to bring a collapsible duffel bag in the bottom of your suitcase. You can always stuff your dirty laundry in the duffel bag and check it, while stowing your souvenirs in your carry on.
Clothing/Shoes/Weather Gear: No need to dress to impress. While I wouldn't recommend dressing in a burlap bag, I do recommend bringing comfortable clothes. Check the weather before you leave and pack accordingly. Bring an umbrella...we got caught in a torrential downpour without one. If you plan on going to a nice restaurant, bring some nice clothes. Otherwise, casual is the way to go. But most of all, bring comfortable shoes. I tried to dress too cute and paid the price. The second day, I said goodbye to my new sandals and Hello to my beloved New Balance sneakers. Blisters aren't fun!
Toiletries and Medical Supplies: Sun screen...don't forget this or you'll end up looking like a lobster. Bug spray is a good idea since mosquitoes are abundant. A good product is Avon's Skin So Soft Bug Guard with SPF. Works like a charm. If you plan to pack light, bring small travel-size bottles filled with your shampoo, conditoner, body soap, facial cleanser...Try to bring only enough for the duration of your trip, then toss the bottles at the end of the trip. Same with makeup...if you have just a little dab of foundation, take it along and toss it out there. Leaves more room for souvenirs.
Don't forget bandaids, Tylenol or Ibuprofen, stomach ailment aids, aloe gel in case you get sunburned, etc.
Photo Equipment: So much to see here, not enough film! I opted for digital this trip, so I took 3 memory cards. Bought a fourth one while there. I like to take photos (esp. of Houses I'd Like To Live In). Digital cameras and memory cards will not be damaged going through the x-rays in the airports. Just don't check them! They could end up "missing."
If you go the film route, make sure your film is hand-inspected or you could run the risk of having your film damaged.
Camping/Beach/Outdoor Gear: Don't forget the bug spray and sun block!
Clothing/Shoes/Weather Gear: Remember it's always best to look ahead at the weather forecast for where you are visiting instead of dressing for the weather you live in. It can get chilly here and even on a "warm sunny day" there can be a chill do to the wind. We always dress in layers and bring extra colder weather items just in case.
buy supplies in larger towns
Clothing/Shoes/Weather Gear: The saying goes : If you don't like Maine weather wait a minute it will change. So bring along various weights of clothing . and a hat for summer downpours
Camping/Beach/Outdoor Gear: have a hat and waterproof foot wear
Luggage and bags: Bring a small travel bag, ready with camera of course, but alternate clothing as well because of the unknown weather shifts.