JMU is not the easiest to get to by public transportation, but during the academic year there are shuttles that run on school breaks… http://www.jmu.edu/transportation/regional-transportation/charter-buses.shtml
There is also a small airport that runs to Dulles… http://www.jmu.edu/transportation/regional-transportation/airports.shtml
and an Amtrak station in Staunton… http://www.jmu.edu/transportation/regional-transportation/amtrak.shtml
There are also shuttle services… http://www.jmu.edu/transportation/regional-transportation/taxi-shuttle.shtml
There is both Amtrak and an airport in Charlottesville (about 1 hour away)
Here is more information about transportation… http://www.jmu.edu/transportation/index.shtml
So, no the MOST convenient. but lots of options.
A 3.3 and a 27 ACT would not necessarily be a problem, particularly with a recommendation from the program to academic admissions.