Acutally, in the constiutional convention, one draft had the president with a single, seven-year term -
The Executive power of the United States shall be vested in a single person. His style shall be,'' The President of the United States of America," and his title shall be, "His Excellency." He shall be elected by ballot by the Legislature. He shall hold office during the term of seven years; but shall not be elected a second time.
Therefore I see -
1789-96 - George Washington
1796-1803 - John Adams
1803-10 - Thomas Jefferson
The next few Presidents are pretty easy, since most of the first ones served two terms with friendly congresses anyway. Afterward is anyone's guess.