There are direct flights to Portland International Jetport via Southwest Airlines and other carriers, however, we've found that the more economical option is to fly to Boston (Boston Logan International Airport.)
To avoid renting a car, there is the option to ride Concord Coach Lines directly from the airport terminal to Portland. Round-trip bus tickets are $50/person. We always ride the bus and it usually takes just under two hours. The bus system in New England is nothing like what you're used to - it's clean, they show movies, have WiFi, restrooms, etc. Once you arrive to Portland, Uber/Lyft is readily available. The wedding venue is approximately 13 minutes from downtown Portland.
July is peak season and vacation rentals/hotels are reaching capacity quickly. Our best suggestion for the most cost-effective accommodations is to consider AirBnB or VRBO, both linked below.