Matt said on Facebook just today that due to lack of interest and his own schedule, he won't be organizing the Salem trip any more. However people should feel free to organize their own trip!
Google Maps says it's roughly an hour and a half from Warwick RI to Salem, MA. However I doubt it's taking the sheer traffic insanity of Salem on the weekend before Halloween into account, so leave plenty of time. This is Salem's high season.
The best source of information on Halloween happenings in Salem is http://hauntedhappenings.org/
. It includes transportation and parking information.