Henry Knox.....he was 25 when the war started...
http://en.wikipedia.org/wiki/Henry_Knox
As the Siege of Boston continued, he suggested that the cannons then at recently captured Fort Ticonderoga could have a decisive impact. Washington commissioned him to colonel and gave him charge of an expedition to retrieve them. His force brought them by ox-drawn sled south along the west bank of the Hudson River from Fort Ticonderoga to Albany, where they crossed the Hudson and then continued east through The Berkshires and finally to Boston. A map of the trail taken by Knox and his men can be seen by clicking this link Along this trail are at various points plaques denoting the historic event. One of these plaques can be viewed by clicking this link There are 56 identical plaques on the trail from Fort Ticonderoga to Cambridge, Massachusetts denoting the approximately 56 day length of the journey. Knox and his men averaged approximately 5 ⅜ miles per day, completing the 300 mile trip in 56 days, between December 5th, 1775, and January 24th, 1776. The Cannon Train was composed of fifty-nine cannon and mortars, and weighed a total of 60 tons. Upon their arrival in Cambridge, when Washington's army took the Heights of Dorchester, the cannons were placed in a heavily fortified position overlooking Boston, from which they seriously threatened the British fleet in the harbor (see fortification of Dorchester Heights). As a result, the British were forced to withdraw to Halifax on March 17, 1776. After the siege was lifted, Knox undertook the construction and improvement of defenses in Connecticut and Rhode Island to prepare for the British return.