Yes. It's a rural area, so there's no Uber. You'll need a car per party / family / friend group. Many of you will likely be driving up anyways, but If you're flying or taking a bus to Bangor, Portland or Boston, you may be able to rent a car there.
Yes, there will be parking at the venue (they are at the same venue). Carpooling and arranging designated drivers is encouraged.
Yes, the ceremony will be held outside, weather permitting. If it is raining, the ceremony will be held in a tent. It's late June, so be prepared for chilly or hot weather. The reception will be held indoors in a temperature-controlled space.
Unless explicitly invited (their name will appear on the save the date or invitation, or it will be addressed to your whole family), no. There is limited space at the venue, so we appreciate everyone's understanding!