Welcome to the Southern Maine area! I'm not sure you could think of two places more different than Maine and California... ha.
We do have commutes but we don't have traffic, so it's what I call "driving commute." For example, plenty of Maine people work in larger towns and cities, but live in rural communities within about 45 mins - 1 hour drive. The southern Maine region has a significant population of folks who work in Boston and commute in to the city daily or occasionally. But to use your example, if I live in Westbrook, I'm in downtown Portland in about 10-15 minutes max.
The market in the Portland area is hot for Maine, but I know it'll probably look inexpensive to someone acclimated to the California market. That said, I would advise you to find a good real estate agent/office with good knowledge of the multifamily market to help you find something that works for you. There is a great deal of competition, particularly in the niche you're considering -- owner occupy. If you can spend the time before you actually move really developing a set of criteria, you'll be ready to jump on the ideal property when it comes up.
We just added 2 buildings in Westbrook to our portfolio this year, and I've been really pleased by how well they're operating even in year 1. The market for rentals there is strong, and there is still some opportunity to add value if you know what you're doing.
Best of luck to you!
PS - Yes, we have snow. You'll want to budget for something called "snow tires." ;)