I live in the Rumford area and can tell you a bit about it. Feel free to PM if you want more specifics.
Ocean - from Rumford, it is a bit further away than in the other locations you are concidering but it is quite easy to take a day trip to the ocean from the Rumford area.
Big trees and forests - defintiely have those!! and lots and lots of them. Wood products and wood industry supplies a lot of jobs around here. This area has many small mountains covered in trees - gorgeous veiws everywhere beautiful hikes in tree shaded paths are abundant.
A need for midwives in this area - definitely! I had to do a lot of searching to find a HB midwife to come to my home - she is over an hour away. She still doesn't have a backup midwife to come to me for the birth as most others are 1.5-2 hours away and it won't work for their schedules. It is a lot of miles and in bad weather, those driving times could easily be doubled. There used to be a CNM/NP that worked at the Rumford Hospital but she left over five years ago and they got another OB/GYN instead
Too bad because she was a CNM/NP and was the only female primary care health provider that could also deliver babies. The central location of Rumford could provide a lot of midwifery outreach to areas that have little or no midwifery options (areas near Rangely, Farmington, Bethel/Newery, etc.)
City v. town v. rural life: Your choices out here (Rumford area) are town or rural life both of which are much different than the bigger cities in Maine (Portland, Lewiston/Auburn, Bangor). You definietly need to check out any town personally before you get your heart set on one. They all have their own quirks. Rumford proper has a paper mill which IMO stinks far too much for me to ever live in town. However, one can easily live 10 minutes away and not have that problem. The town has a natural food store, medium-sized grocery store, drug store, Walmart and a few dozen other little shops/stores/services. A little bit of culture but you can also drive a bit (30-60 minsutes) and have more of that. LOTS of outdoor recreation!! You can usually get most of your daily/weekly shopping needs done in the area. Lots of craft fairs in the fall and winter. Lots of folks that are artisans or make lovely handmade items - you could get anything made or grown for you here. Bigger box stores are about 40 minutes away in Lewiston/Auburn or Augusta. People are nice and you really get to know them rather quickly especially if you ask for advise
Generally, most folks are hard working and practical people. You can live a bit further away and live in a rural area - fresh air, more land, fewer neighbors but you will be in your car a lot more. You could live right in the middle of a pine or hardwood forest and still be about 10-30 minutes from town. I really love the rural lifestyle here!
Alternative Culture and community: There is some of that in the Rumford area but not as much as the other areas which you are concidering (natural foods, food coops, CSAs & farmers market, yoga, other crunchy/natural folks, organic farms, homeschoolers). There is more alternative culture closer to Farmington (due to the University there) and the Bethel area which are both relatively close to Rumford.
Weather: it is cold
most of the year but the summers are usually fantastic, autumn colors are amazing especially because of the mountains. We are in zone 4 for growing but depending on exactly where you live you might be in a slightly warmer or colder pocket. Elevation in this area makes a big difference. The rumford area is a bit colder and has a shorter growing season than the other places you are concidering near the coast. On the coast, spring thaw/last frost is about 3 weeks ahead of Rumford. We can get heavy snows but usually less ice than the coastal areas. Roads are fairly well maintained but in heavy snows, it just takes a while to clear everything. Snow tires are usually needed.
Politics: this really varies from town to town - in general, I think Rumford is socially conservative but easily votes in most democrats.
Other info on Rumford that might be of interest to a midwife: The average income in this area is lower than much of the state, many people receive some sort of government assistance. This is espeically true in the Town of Rumford. The closer you get to Bethel or Farmington or Lewiston/Auburn, the income goes up more. However, property prices are also lower and there can be some very good buys in the Rumford area. It seems that teenage pregnancy is fairly common as well as single young moms. There is not a lot of jobs available in the immediate area if you are looking for one for a spouse/partner. They may have to drive to Augusta/Lewiston for work.
I hope this helps. If you have any specific questions on the area, let me know.