Khorod said:The trick really is that the countryside is not coated with 'adventurers'. ... But in most other cases it starts to smell funny if every PC, every 5th NPC, and anyone on a country road...
Then get out of your 21th century city!

Until the 1900s, almost everyone was on the country road, so to speak. There seemes to be a concept in the 20th century that people have to "make it" in the big city to be the "real deal." I suppose part of that deal is thanks to the romantic, modernized versions of Camelot.
Truth be told, most knights had the biggest house on their land and that was it. And most of their income came from ... managing their serfs to farm. Knights knew horses as part of what they knew about livestock. The closest analogy the 20th Century America had to knights was the Southern Gentleman and his plantation. Funny enough, a lot of those fellows saw themselves as gentleman adventures as well.
Perhaps part of the reason why we have so many stories about knights and heroes proving themselves again and again is because they had to in order to distinguish themselves from the "country bumpkin" adventure that was "anyone on the country road."
Heck, most of these duels, challenges and joust on in these stories start out with "Oh, you claim to be a real hero (or later in the saga, "Oh you claim to be that famous hero), but lets see you prove it." No TV, no newspaper and not many trips into the same towns (and the lack of a publicist) doesn't give the general populous much to go on to distinguish a hero from a copy cat con aritist.
I suggest checking out the Pendragon RPG. It is a great break from regular DnD and it is enlightening how poor and rural historical knights really were. Based off that game, I discovered an interesting question:
What make a hero truley noble?
Fighting off an army that wants to invade his lands (and only source of income?)
OR
Sleeping in the leaky barn during a storm because he refuses to kick a family out of their home because it is the only shelter for miles and miles (no inns and magic shoppes exist in Pendragon) even though it is his right to do so.