I have lived and worked on Fleming Island for the past 13 years. LIke you I am a transplant from the Northeast (I grew up in New York, and got my first job in Massachusetts). My wife and I had the opportunity to transfer away from Fleming Island and Northeast Florida, but chose to stay here for the combination of low cost of living, great real estate property values, fantastic weather, good schools, and a ton of things to do including golf, beach, and other outdoor activities.
Fleming Island offers a number of diverse communities with lots of amenities like splash parks and pools, tennis courts, soccer fields, biking trails, and golf courses. There are a number of gated communities on Fleming Island; I live in one called Pace Island. Pace Island offers single family homes of various sizes and price ranges. There are small patio style homes that are perfect for empty nesters, larger homes with 4-5 bedrooms that seem to have a lot of families with kids, and large estate homes that are typically over 3500 sq ft and many are on Doctors Lake with private boat docks.
There are two gated communities called Amberwood and Lake Ridge South that feature paired villas (the term you may be familiar with is "duplex"). My mother-in-law and father-in-law live in Amberwood and have a number of friends with similar interests that live there as well (most of their mahjong and card playing friends live in the neighborhood). The villas in these communities are between 1500 and 1800 sq ft with 3 bedrooms and 2 bathrooms. My in-laws love them because they were perfect for them as they downsized from a large home in the Northeast.
Fleming Island is located in Clay County, which is just southeast of Jacksonville. The Clay County school system is one of the best school systems in Florida and attracts a lot of families that want good schools but don't want to pay for private school. The three elementary schools, two junior high schools, and one high school Fleming Island is currently zoned for are all A-rated schools. The great school system helps maintain resale values in the area.
You noted that the price per square foot seems low. Everything is relative and having lived in MA I can relate to your perception that prices are much lower than in MA. Part of the reason that the overall price per square foot on Fleming Island is lower is because of one large planned community called Fleming Island Plantation was built at the height of the real estate boom and many homeowners there are underwater in their home values. Like many homeowners that purchased in 2003-2007 some of them in Fleming Island Plantation have had to short sale their homes or let them go into foreclosure if they are forced to move or lose a job. The higher number of short sales and foreclosures are keeping prices on Fleming Island lower, but offer great deals to people that relocate here.
If you have specific questions you'd like me to address, or if you want help finding a home on Fleming Island, please don't hesitate to contact me.
Good luck in your search, and I hope to bump into you in the near future in Fleming Island.
Prudential Network Realty
3535 Highway 17, Suite 10
Fleming Island, FL 32003
Eagle Harbor, Fleming Island Plantation in Clay County Fleming Island and St Johns Golf and Country Club in St Johns County would all be worth looking at. Schools may not matter personally but they always help with resale. You will find find fun and active tennis communities as well as affordable golf all in well designed neighborhoods with a various price range of homes to accomodate diferent lifestyles. I hope this helps. Feel free to call me for more details than can be given in this format.