Just a quick question:
Does turning the clock backwards reset stuff like fossils, the money rock, shops, etc., like they do if you turn the clock forwards?
From what I noticed, time travelling backwards changes shop stock and turnip prices, but new fossils don't appear, and flowers, trees and bushes do not grow. Also, if you buy an upgrade/exterior customization from Nook's, it won't show up until you TT a day forward. Same with ordering items from the catalog - TTing backwards doesn't count as a day, and no mail will appear.
I haven't really payed attention to the money/gem rocks, so I'm not sure how TTing backwards affects that.
There is no "backwards" in the game. Each different day you login will be counted as +1 for your town regardless of it's date. Going back some hours without passing 6AM still works I think (haven't tried), but the game will notice a time shift which has some negative effects like bad turnip prices.