Hi Steve, you are knee deep in NETCA territory (New England Div of the Train Collectors Assoc). There is a meet coming up the last week of the month (outdoors) you will find more detailed info at www.netca.org
Also - the Boston Metro Hi-Railers is a good group of people. While certainly not south of Boston - they are in the area.
Come down to RI when the weather gets warmer, there are a few of us who like to drink trains and talk beverages at the local waterside establishments.
Or if your handy - you could come by my house and help get my layout started
Paul