I commute via train and bike from Fredericksburg, VA to Fort Belvoir, past MCB Quantico. A bunch of Marines go from Fred to the main side base and commute from there. I go from Springfield to Fort Belvoir and back every day. Average almost 100 miles a week. My 61 year old legs and heart never felt better, except when I was 35 and riding my way through the FBI academy on base.