did he serve america by going abroad to perform duties?
Yes, as ambassador to the Dutch Republic and Great Britain
John Adams
In mid-1780, Adams traveled to the Dutch Republic. One of the few other existing republics at the time, Adams thought it might be sympathetic to the American cause. 
who was the declaration of independence written by It was drafted by The Committee of Five, whose members included John Adams and Thomas Jefferson among others who signed it? Representatives of New Hampshire, New York, Connecticut and others when was it published? 4 July, 1776 was there a preamble? Yes, written by John Adams what was this person's profession? He was an American statesman, attorney, diplomat and writer. did he go to college? Yes, to Harvard College what were his religious views? Historian G.S Wood believes that he denied the miracles of the Bible, but always respected the religiosity of people, while Everett thinks that he believed in a religion based on reason and common sense.
wiki:21616635
John Adams [SEP] Ambassador to the Dutch Republic
In mid-1780, Adams traveled to the Dutch Republic. One of the few other existing republics at the time, Adams thought it might be sympathetic to the American cause. Securing a Dutch loan could increase American independence from France and pressure Britain into peace. At first, Adams had no official status, but in July he was formally given permission to negotiate for a loan and took up residence in Amsterdam in August. Adams was originally optimistic and greatly enjoyed the city, but soon became disappointed. The Dutch, fearing British retaliation, refused to meet Adams. Before he had arrived, the British found out about secret aid the Dutch had sent to the Americans, the British authorized reprisals against their ships, which only increased their apprehension.