If you're looking to save a few bucks, consider flying into Boston and taking the bus up to Portland! The coach line has great ratings and will make your travel quick and easy. From the drop-off point you could take an Uber to wherever you want to go whether that's up to Freeport and the inn for check-in or to the Portland airport to pickup a rental car. The link for the coach line is below.

https://concordcoachlines.com/route/portland-me-to-from-boston-logan-airport/

If you're traveling out of the Portland airport, be sure to get there early so you can spend some time at their puzzle table! It usually moves around a bit so you might have to go looking, but it's a great way to kill some time before your flight!