This is an assignment that I give every year--Chaucer's work is regaled as the very first collection of short stories (as we know them). He tells the truth as he sees it, and sometimes he doesn't have to say what he means...we read between the lines. He is excellent at both direct and indirect characterization.
In Chaucer's time, just as our own, we often make assumptions about people based on their posture, the way they dress, fix their hair, if they meet our eyes when we are talking to them, do they fidget? Our speech, accent, pronunciation says a lot about us today, as it did then. The way we react to things and how others react to us says a lot about character. Foul language would indicate, perhaps, low upbringing or low character--perhaps lack of education. Using overly large and obscure language may indicate snobbishness or someone who is attempting to appear educated when really he/she is lacking.
You would have to put the whole picture together to get the final portrait--if one or two of the things done or said are not meshing, it is up to you as the reader to discover what Chaucer is saying about that person or what the truth is about that person.
Not much has changed in humanity today from his time. We are still greedy, power-hungry, in love, lust, hate, envy, and wanting to seem more important than we really are.
The occupations may be different for today's group, but the actions and personalities are very similar.
Let's imagine that we're rewriting the Tales to set them in the 21st century. First of all, we'd have to find a reason other than religion for them to be traveling. In the 14th century, people regularly went on pilgrimage to a shrine for healing or to ask for special prayer. Today, some groups, particularly in Islam, still practice the pilgrimage, but few Christians do.
The modes of travel would have to change. Chaucer's pilgrims mostly rode donkeys, with the wealthy riding horses. Today, people travel by car. Our travelers would probably ride in a comfortable, air-conditioned bus.
Occupations have changed. While we still have religious orders and might still include a prioress, a parson, and a friar, there would be no summoner or pardoner. We would still have a merchant, a cook, and a lawyer, but we wouldn't have a tapestry weaver, a dyer, or a miller. We'd have to rename some of the pilgrims. For instance, the Reeve would be called a Caretaker, the Manciple might be a Paralegal, the Franklin would be called a landowner. We might still have a knight, but he would not likely be a soldier returning from war. Today people are knighted because of some great deed they've done.
There was government corruption in the 14th century, and there is government corruption today. There were poor people then and now. There was drinking then and now.
You might find that there are just as many similarities between Chaucer's pilgrims and people today as there are differences!