Highest on my list of priorities is custom and etiquette; I can't seem to find anything that gives me a clear idea of the basic standards of interaction. (It doesn't help that I'm not sure how to search; "edo period customs" and "edo period etiquette" don't seem to turn up anything useful.)
What I specifically need to know is: if a traveling merchant (a medicine seller, specifically,) visits the home of a local lord in a small village, how would he be received? Who would be likely to meet him and present him to the lord? How would he be presented to the lord? How would the lord address and behave toward him, and how would the merchant be expected to conduct himself in return?
If specifics are helpful: the lord in question is fairly young (early-to-mid 20s,) and of a somewhat bohemian nature; he's very eccentric and rumor has it he's going mad. His estate is in a state of decline, and many of his servants have left him. The merchant in question is there under the pretense of selling medicine, but actually came to slay a demon.
Another less pressing but still important question: Would there have been a way during this time and place to preserve a dead body for years and years without it decaying? In other words, to keep it beautiful after death?