The perception I always have about medieval peasants was a Ethiopian-skinny and dirty man that look like he brushes his teeth with battery acid. He wouldn't know much about people or life outside his village, he might know something about nobility and who the king was but most everything he knew socially were stereotypes or rumors. He'd live his entire life working very hard dusk till dawn, maybe having Sundays off but overall he would have almost no free time and nothing really to do in his free time anyways. He would meet his end at age 45 give or take. His life was very miserable and empty, but too ignorant to know much better so it was fine for him. I know it's probably wrong, but how wrong is the perception.
I know it's a big question but try to answer as well as you can.
I have several other questions about people in pre modern times.
• When did most people stop being stunted in height and very skinny, and start being what would be normal shape of modernity?
• When and where was the first time where most of the population was literate? What contributed to increasing literacy?
• How much knowledge would a peasant in medieval France know of Spain, England, or Germany? Were they ever likely to meet someone from another country?
•Similar to the previous question, but how much would a Roman average joe know about other Roman provinces (or empires/kingdoms)?
• How much of history did the common people know? Not all people who saw Shakespeare's plays were elite and educated, would they have any idea who Caesar and Cicero were? Or did they just watch the play for the ghosts and stabbings? Would the complex messages of those plays be lost to most of them?
• How brutal was work? Would your average joe today kill himself after one day of working as a serf or on a latitudinal?
Any answer to any of these questions would be nice.
Based on archaeological excavations, it seems that the average height in northwestern Europe peaked around 1000 CE, and as population density increased, and the average standard of living dropped, so too did height, until it reached its minimum around 1700-1800. It's since increased slightly above the early medieval height, but not too much; from 5'7"-5'8" to about 5'9"-5'10". Obviously, famines were an issue, but they were not omnipresent. There's really no reason to think that, during healthy economic/agricultural periods, people were particularly emaciated.
Widespread literacy is really a post medieval thing. Prior to about 1100, almost no one who was not a cleric (affiliated with the church) was literate, but it does seem to have become increasingly common for aristocrats and merchants to read and write. We know, for instance, that Richard I, who lived at the end of the 12th century, was literate and fluent in Latin and two forms of French (langue d'oc and langue d'ouil).
I can't answer this, mostly owing to a lack of sources. There's very little from my period (the High Middle Ages) dealing with common folk. Almost everything was written by or for the aristocracy and the clergy. That said, you are correct that most people had very limited travel, but this is not a peculiarly medieval aspect. I would venture to guess that, prior to 1800, it was at least fairly unusual for common people to travel beyond the area they grew up in, barring such things as military service abroad. Foreign merchants might be present at market fairs, so this might well be the only regular contact countrymen had with people from outside their area. Of course, pilgrimages were a feature of medieval life, but this was typically a once-in-a-lifetime event.
I cannot speak to this at all.
Biblical stories would of course be known, as would folklore and other oral traditions. But in terms of actual history? Very unlikely. There were of course educated people during this period, but you would be unlikely to find a university-educated person in a Hampshire village.
There was tremendous variation in the lives of the peasantry. There were independent sokemen and yeomen, who formed the closest thing to a rural middle class (though that's a very problematic term), free peasants, who were comparatively wealthy and owed limited or nonexistent manorial obligations beyond a fixed rent, and there were very poor cottagers who lived quite meanly and owed quite a lot of their time to the owner of the manor. That said, an agricultural lifestyle is not in any way comparable to our modern lifestyle of daily and hourly work. There were periods at which frantic activity were required (harvest and planting times), and other times when there was less work to be done. That's to say nothing of the many holidays and feast days, on which at least theoretically people were not supposed to labor. Suffice to say, a life of hard work should not be confused with a life of constant work.
One of your questions is about the Roman "average joe" and his knowledge of other Roman provinces. By the third century, the Roman world had become quite cosmopolitan. Large-scale trade connected most of the empire, and created a class of people who were "Romanized" as a result. Essentially, they took on a veneer of Roman culture, obtained through books which summarized "romanitas." In fact, this is when the West started speaking Latin. It wasn't forced on them, but it became advantageous to do so, because it linked an individual in with this larger economic world. Note that we're not talking about the Senatorial class here (which probably Romanized quite a bit earlier), but about better-off Plebians were were engaged in commerce. So, even though an individual person might not actually visit Rome (or Alexandria, or Constantinople, or Marseilles), they might not be too far removed from someone who did (a brother-in-law who traded in olive oil, who thus knew a guy who'd sail the Mediterranean, for example).
Peter Brown, in The World of Late Antiquity, talks about this. A game-changing work, well worth reading.