What was the educational level of most Americans at the founding? The question relies on an abstract 'standardized' measurement. It is in itself based on the modern schooling paradigm.
Remove the television and radios, the Scholastics Aptitude Tests and Intelligence Quotients created in the early 20th century. People involved themselves in reading the exceptional literature of the time, discussing current politics and philosphy at the local tavern, writing and distributing rhetorical pamphlets or analyzing and responding with their own pamphlets, participating as entrepreurs in local economies, etc. Who has more REAL human education, these types or your literal 'run of the mill' college graduate who has been purposefully guided by instructors, learning by rote?
People like Thomas Paine, Ben Franklin and George Washington had very little schooling. While they are considered as some sort of elite in modern conception, there was actually little that differentiated them from other colonists. Think about this: between the time independence was declared and the time an actual constitution was drafted, the colonists essentially self-governed. Try that today with all of our dependencies.
Not to say that there are not any truly educated people... just that other factors than forced state schooling have more to do with someone aquiring an intellectual education. Usually, its the influence of people your life that appreciate intellect and your natural desires to find the truth in whatever you experience.